In the Grow - Q & A

Q. My mimosa tree has split down the middle of the trunk. Is there any way to save it? Or should I just take it down?

A. Split trunks are a common problem with multi-trunked species such as mimosa. Split trunk is a significant factor for a "risk tree," if it is sited where damage to humans, pets or property could occur when, or if, the tree falls. Cabling and bracing can be completed by a certified arborist to help provide structural support, but the split will still be a weak point in the tree, susceptible to disease, insect pests, decay and further splitting.  <Read More>

Video - Recovery of Your Lawn After a Stressful Summer

Many homeowners with drought-damaged lawns have decisions to make about how to repair them after a stressful summer. Purdue turf grass Extension specialist Aaron Patton gives advice and information on reseeding and fertilizing to help your lawn recover.

For addtional drought management and recovery information, be sure keep checking the Purdue Drought Information website.

In the Grow - Q & A

Q. We have had the pictured vine above our sink since 1977. It has never bloomed in all that time - until this spring. It bloomed for the very first time. We don't know the name of the vine and would like to know. Our daughter told us it is a common vine. What can you tell us?

A. Wax plant, known botanically as Hoya carnosa, is a popular, easy-to-grow houseplant. This vigorous, twining vine may take years before it is mature enough to bloom, but once it does, it often continues blooming for months. Wax plant performs best in bright light with a well-drained soil mix that is allowed to dry a bit between waterings. This species seems to prefer being a bit pot-bound, so don't be in too much of a hurry to repot, even if it seems overgrown for its container.

Q. I have a question about cedar and bark and any wood chips for mulch. Will these chips attract termites?

A. Mulch of any kind can create a stable, moist habitat favorable to termites, so if termites are already in the area, or happen to wander into the area, you might see them in or under the mulch while they forage.  <Read More>

September Home, Yard, and Garden Calendar

HOME (Indoor plants and activities)

Prepare storage areas for overwintering tender flower bulbs and garden produce.

Thanksgiving (or Christmas) cactus can be forced into bloom for the Thanksgiving holidays. Provide 15 hours of complete darkness each day, for instance, from 5 p.m. to 8 a.m., for approximately eight weeks. Keep temperature at about 60 to 65F. Temperatures of 55F will cause flower buds to set without dark treatment.

YARD (Lawns, woody ornamentals and fruits)

Fall is usually a good time to plant many container-grown or balled-and-burlapped nursery stock, but if your area is still suffering from drought, it might be best to wait for better conditions. You do not want new plantings to go into winter in drought condition.

If you do have sufficient rainfall or ability to irrigate new plantings, prepare a hole wider than the plant’s rootball, plant at the same depth it grew in the nursery, and water thoroughly. Mulching will help protect against large fluctuations in soil temperature and moisture. Be sure to stake or guy-wire tall plants during their first season to protect them from strong winds.

GARDEN (Vegetables, small fruits and flowers)

Dig up onions and garlic after tops fall over naturally and necks begin to dry.

Plant radishes, green onion sets, lettuce and spinach for fall harvest.

Thin out fall crops such as lettuce and carrots that were planted earlier.  <Read More>

Stressed Plants May Look Like Early Fall

To state the obvious, many of our landscape plants really show the signs of excessive heat and extreme drought. Some trees are losing leaves already and may be turning color before they drop. Others have turned completely brown while still remaining attached.

Early fall color and/or defoliation is common when plants are under stress and this season has been quite challenging for many trees, both old and young. The intense heat made it difficult for plants to keep up with water and cooling requirements, even in areas where moisture was adequate. Combine extreme heat with drought, and it is a wonder any plants survive.  <Read More>

Upcoming Events - Purdue Master Gardener Course to be Offered this Fall

If you enjoy gardening and enjoy “Helping Others Grow”, make plans to take part in this fall’s Purdue Master Gardener Course in Spencer County.   

The Purdue Master Gardener Program is a volunteer training program which offers an extensive course in horticulture in exchange for a donation of volunteer hours to help teach others what you have learned. 

The course will be held on twelve consecutive Monday evenings from 6:00-9:00 PM, beginning September 10, at the Spencer County Youth and Community Center in Chrisney, IN. 

Participants will be exposed to a wide range of subjects including soil and plant science, diagnosis of plant problems, pesticide safety, composting, and culture of vegetable, flower, landscape, and fruit plants.   

A $125 per person supply fee will be charged to cover such items as reference materials, mailings, name badges, and refreshments. Couples or two family members who wish to take the course together and share reference materials can register for $200 per couple. Registration deadline is August 31.    

If you'd like an application to join our new team of volunteers or have questions about the program, please contact Nicholas Held at the Spencer County-Purdue Extension Office at (812) 649-6022 or nheld@purdue.edu.  Applications are also available online.

August Home, Yard, and Garden Calendar

HOME (Indoor plants and activities)

Take cuttings from plants such as impatiens, coleus, geraniums and wax begonias to overwinter indoors. Root the cuttings in media such as moist vermiculite, perlite, peat moss or potting soil, rather than water.

Order spring-flowering bulbs for fall planting.

YARD (Lawns, woody ornamentals and fruits)

Newly established plants are particularly vulnerable to extreme heat and drought. If possible, apply 1 to 1.5 inches of water every 7 to 10 days as a gentle, thorough soaking.

Even well-established trees, shrubs and perennials will suffer from extreme heat coupled with drought. Symptoms may include wilting, leaf scorch, branch dieback, blossom drop, early "fall" color and leaf drop, and in some cases, plant death of specimens that were already ailing.

GARDEN (Vegetables, small fruits and flowers)

Temperatures above 90 F often leads to poor fruit set in most vegetable crops; upper 90s will stop fruit set in nearly all crops. Fruits that were already set may show uneven ripening, blossom-end rot, skin cracking, sunburn where foliage cover is poor, poor ear fill in corn and bitter flavor in cucumbers and other vegetables.

Keep the garden well watered during dry weather and free of weeds, insects and disease. Early morning is the best time to water, but areas under watering restrictions may need to adjust accordingly. While normally we discourage overhead sprinkling due to its inefficiency and potential for promoting plant disease, it can be very effective at decreasing temperature in the plant tissue.  <Read More> 

In Times of Drought

Dry summers are not that unusual in the Midwest, but this year's dry spell - and now drought in many areas - has come considerably earlier than usual. Summer is just now officially getting started!

Gardeners have a battle on their hands to keep plants healthy when extremely high temperatures are accompanied by lack of rain. During prolonged drought conditions, water restrictions or just limited ability to water to a huge number of plants, you may have to limit watering and prioritize which plants will be rescued - a bit of garden triage, so to speak.  <Read More>

In Times of Drought - Video

This video is a companion piece to the above article and features Rosie Lerner, Purdue Extension Consumer Horticulture Specialist, covering some basics of helping your vegetable and landscape cope with the drought. 

Extreme Drought and Heat Wave - Not a Good Combination

In the previous drought post, it was noted that if upcoming rainfall chances did not materialize, we could be at a tipping point for much worse drought conditions.  Well, as we all know, those weather systems did not materialize and we are seeing increasingly widespread drought effects on crops, lawns, and gardens.  This week's US Drought Monitor report has placed the majority of Spencer County in the the "extreme" category and the 7-day forecast from the National Weather Service indicates 100+ degree temperatures each day with no chance of rain. 

Purdue Extension and the Extension Disaster Education Network have developed a drought information website that compiles drought management tips and resources for consumers, homeowners, and agricultural producers.  This site will continue to be updated with information as long as the drought conditions persist.  I encourage you to check out this this regularly for updates.   

Also, two articles have recently been released addressing the continued drought effects on corn and soybean production.  Links to those publications are listed below:

Hot & Dry: Stress on the Corn Crop Escalates

Signs of Drought Stress in Soybeans

Drought....and the Potential for More Drought

US Drought Monitor report for Indiana.  For more information, see the Drought Monitor website.

This week's US Drought Monitor Report indicates an increasing area of Indiana is now under a moderate or severe drought, with a portion of southwest Indiana falling under the "severe" category.  While certain aspects of the current drought conditions have some producers and others thinking "1988" in the back of their minds, it is too early to make such a prediction.

So far, Spencer County has fared better than our neighbors to the west and northwest.  Though we are in the moderate drought category, infrequent but timely rainfall, combined with cooler temperatures, especially overnight, have kept drought effects in crops, gardens, and home landscapes from becoming widespread.   

There is a slight chance of scattered showers this weekend but according to staff at the Indiana State Climate Office, the next chance for more widespread, substantial rainfall is not until late next week.  As a result, we are in a bit of a wait-and-see pattern as far as how the drought will progress, with the next 10-14 days being crucial.  If one or both of these predicted systems produce rainfall,  it could be just the timely rain event we need to hold off further drought progression, at least for a few more weeks.  However, if these systems fail to bring moisture, we could then be at the tipping point for something much more severe. 

As we watch how the situation progresses over the next two weeks, we will continue to post drought management information on the Gazette, on our Facebook page, and in our bi-monthly newsletter.  In the meantime, below are two articles addressing the topic.  The first is a recent article covering the effects we are currently seeing in corn and soybean crops.  The second, originally written in 2007, covers tips for home gardens and landscapes.

More Crops Affected as Drought Spreads Throughout Indiana

Help Your Garden Cope with Dry Spell

May Home, Yard, and Garden Calendar

HOME (Indoor plants and activities)

Many indoor plants can be moved to shady locations outdoors but only after danger of frost is past. Plants will dry out more often outdoors, so keep a close eye on soil moisture. Sinking the pots in soil will help slow down moisture loss.

YARD (Lawns, woody ornamentals and fruits)

Prune early spring-flowering trees and shrubs after flowers fade.

Plant balled-and-burlapped or container nursery stock, and water thoroughly.

GARDEN (Vegetables, small fruits and flowers)

Plant frost-tender plants after danger of frost is past for your area. This includes warm-season vegetables, such as tomatoes, peppers, eggplant and vine crops, as well as most annual flowers and tender perennials, such as cannas, gladiolus, dahlias, tuberous begonias and caladiums.

Pinch chrysanthemums and annual flower plants to keep them compact and well branched. <Read More>

Growing Fruits and Vegetables in Containers

If you lack adequate space for a full-fledged garden but still would still like to enjoy a few fresh fruits and vegetables this summer, container gardening may be the answer for you. Flowers are not the only plants that do well in containers. In fact, most fruits and vegetables have varieties which will do well in containers. Strawberries are the most common container fruit while tomatoes are the most common container vegetable. Lettuce, green onions, radishes, cucumbers, and peas are also popular choices.

An increasing number of varieties are developed each year that are adapted for limited space areas; everything from grafted dwarf fruit trees to bush-type cucumbers. In seed catalog descriptions, many companies specify use in containers for small-size fruits and vegetables.

Just about any container can be used to grow fruits and vegetables; from whiskey barrels and bushel baskets to clay pots and hanging baskets. The key to success is to make sure the container provides adequate drainage. Water should not be allowed to stand in the bottom of the container. To provide proper drainage, the container should have holes in the bottom to allow the water to run out. The type of soil used can also have an effect on drainage. Garden soil alone should not be used in containers because it will soon become compacted and water will not drain through it properly. Sterilized compost mixed with peat moss and vermiculite works well, as does potting soil mix. You can even use the potting soil bag as the container. Lay the bag flat and slit holes in the bottom for drainage, then turn the bag over and cut openings in the top for the plants. This technique is known as “bag-culture” or “pillow packs”.

The containers should be placed in full sun and should be protected from strong winds. A water source should be close by or the containers should be easy to move so they can be watered regularly, especially during dry spells. You may also need to use portable containers if they are to be used as porch or patio decorations or if they need to be moved to a protected area during the winter. If you have a fruit tree growing in a container, be sure to move it to a protected location in the winter. If left out, the roots will freeze and the tree will die.

Fruits and vegetables grown in containers are still susceptible to the same insects, weeds, and diseases as those grown in garden beds, so it is important to take proper measures to control them. Using a sterilized soil mixture can help avoid soil borne insects and diseases. Removing dead leaves, flowers, and over-ripe fruit will also help control these pests. Inspect the plants regularly for insects and pick them off as you notice them. If the infestation becomes large, it may be necessary to use a pesticide to control them, making sure the chemical is labeled for use on all the plants in the container.  

Weeds are not as much of a problem in container gardens but they can quickly take over if not properly controlled. The best way to control weeds in the container is to make sure the soil in the container does not have weed seeds in it. Potting soil or peat moss generally will not have weed problems but if your soil mixture contains compost or garden soil, these materials should be taken from areas that are not weed infested. If you do find weeds growing in your containers, carefully pull them while they are small. Larger weeds should be cut out so as not to damage the surrounding desirable plants. Herbicide use is not practical for container gardens.

Additional information on container gardening can be found in Purdue Extension publication HO-200, available here.

April Yard and Garden Calendar

HOME (Indoor plants and activities)

Start seeds of warm-season plants, including tomatoes, peppers, eggplant, marigolds, zinnias and petunias, indoors for transplanting later to the garden.

Harden off transplants started earlier in spring before planting outdoors - gradually expose the young plants to outdoor conditions of wind, brighter sunlight and lower moisture.

YARD (Lawns, woody ornamentals and fruits)

Plant a tree in celebration of National Arbor Day, April 27. Bare-root stock should be planted before new top growth begins. Balled- and-burlapped and containerized stock can still be planted later in spring.

Fertilize woody plants before new growth begins. Two pounds of actual nitrogen per 1,000 square feet should be sufficient.

GARDEN (Flowers, vegetables and small fruits)

Plant seeds of cool-season crops directly in the garden, as soon as soil dries enough to be worked. When squeezed, soil should crumble instead of forming a ball. Cool-season crops that can be direct-seeded include peas, lettuce, spinach, carrots, beets, turnips, parsnips and Swiss chard.

Plant transplants of cool-season crops, such as broccoli, cauliflower, cabbage, Brussels sprouts, kohlrabi and onions.  <Read More>

Weird Weather and Pest Predictions

One of the most common questions that has come up in response to this season's winter weather (or lack thereof) is what effect it will have on pest problems this spring or summer, particularly insect populations.  Below are excerpts of responses given by two Extension experts. 

Larry Caplan, Extension Horticulture Educator in Vanderburgh County addressed this question in a recent newspaper column:

I was asked the other day what effect this strange weather will have on our pest problems this year. That is always a very tough topic for me. I don’t like to make predictions, because there are so many variables that can affect future events, rendering my predictions worthless. Still, there are a few things that I expect will happen this season.

First of all, everything will start happening at least 3 weeks earlier than normal because of the long warm-up we’ve had. Crabgrass germination occurs at about the same time as the forsythia shrub blooms. Usually, we can hold off applying our pre-emergent herbicides until mid to late March; this year, though, some parts of the tri-state may already be too late to get the best preventative control.

Dormant oil is applied to fruit trees to prevent later problems with spider mites. The oil needs to be applied before the trees bud out, otherwise the young leaves will be burned by the chemical. It’s already too late in some places. Likewise, the traditional orchard sprays to control disease and insect attacks should begin as the buds open. Normally, gardeners don’t expect to begin this until late March or early April, but I’ve already seen apple and cherry trees in bloom. Be sure to stop spraying while the flowers are open, so that you don’t hurt any bees that may be out.

The repeated storms of the last few weeks have dumped a lot of moisture on the tri-state. With moist conditions and standing water, we can expect increases in biting midges, mosquitoes, and crane flies. This is what we’ve seen for the last couple of years, which have all been pretty wet.

Warm, moist weather is ideal for fire blight, a bacterial disease that attacks apples, crabapples, and pears. The bacteria usually enters the tree through the flowers, but it can also enter twigs damaged by hail storms. Spraying the antibiotic Streptomycin during bloom and after a hail storm may offer some protection.

If warm weather continues, we may see an earlier emergence of Japanese beetles, eastern tent caterpillars, and other pests, but I don’t believe we’ll see increased numbers. Very few of these insects are killed by severe winters, so I don’t think their survival rate will change much.

And from Dr. Rick Foster, Purdue Extension Entomology Specialist, some points focusing specifically on insect populations:

While some insects, such as flea beetles, are directly impacted by cold winter weather and experience greater survival and higher populations as a result of mild winters such as the one we just experienced, many insect species are very well adapted to winter weather and will survive just fine no matter how cold it is.

Most insects have an amazing ability to reproduce in large numbers and, if spring and summer weather is conducive, will be able to develop to serious population levels no matter how many survived the winter.

Finally, some of our pests overwinter indoors and others overwinter in the South, so our winter weather has little effect on their populations.

The bottom line is that for a few insects, we can definitely expect higher populations, but for many others, we just can’t predict.

As you can see, there is no one answer to this seemingly simple question.  While winter weather conditions have little effect on most insect populations, it is the earlier-than-normal emergence of these insects, as well as weeds and diseases, that will be the most likely effect of our mild winter.  And, as Mr. Caplan adds, this is Indiana, so it could snow this weekend and change everything!

March Home, Yard, and Garden Calendar

Rosie Lerner, Purdue Extension Consumer Horticulture Specialist

HOME (Indoor plants and activities)
Begin fertilizing houseplants as new growth appears. Keep spent leaves and flowers removed to improve appearance and encourage more blooms.

Start garden seeds indoors for transplanting outdoors later in spring.

Check stored bulbs and produce for decay; discard damaged items.

Prune, repot and clean houseplants as needed.

YARD (Lawns, woody ornamentals and fruits)
Prune trees and shrubs, except those that bloom early in spring, while plants are still dormant.

Plant new trees and shrubs as soon as soil dries enough to be worked. Plant bare-root plants before they leaf out.

Fertilize woody plants before new growth begins, but after soil temperatures have reached 40 F - it might be several weeks early this year, given the mild winter.

Remove winter coverings from roses as soon as new growth begins. Prune and fertilize as needed.

Apply superior oil spray to control scale insects and mites when tips of leaves start to protrude from buds.

GARDEN (Flowers, vegetables and small fruits)
Plant cool-season vegetables and flowers as soon as the ground has dried enough to work. Do NOT work the soil while it is wet; wait until it crumbles in your hand. If the soil forms a solid ball when squeezed, it's still too wet.

Gradually harden off transplants by setting them outdoors during the daytime for about a week before planting.

Follow last fall's soil test recommendations for fertilizer and pH adjustment. It's not too late to test soil if you missed last year.

Start seeds of warm-season vegetables and flowers indoors; in northern and central Indiana, wait until the end of March or early April. Transplant to the garden after danger of frost is past.

Watch for blooms of early spring bulbs, such as daffodils, squill, crocus, dwarf iris and snowdrops.

Remove old asparagus and rhubarb tops, and sidedress the plants with nitrogen or manure. Plant or transplant asparagus, rhubarb and small fruit plants.

Remove winter mulch from strawberry beds as soon as new growth begins, but keep the mulch nearby to protect against frost and freezes.

Remove weak, diseased or damaged canes from raspberry plants before new growth begins. Remove old fruiting canes if not removed last year, and shorten remaining canes if necessary.

Prune grapevines.

Winter Warm Spell Confuses Landscape and Garden Plants

Larry Caplan, Vanderburgh County Extension Horticulture Educator

I knew this warm spell of the past week was going to be a problem. Sometimes, I hate to be right.

Temperatures in the 50s and 60s have caused a lot of bulbs, perennials, and flowering plants to begin to emerge from the soil and bud out. In my garden, I’ve got crocus and daffodil in bloom. The buds on my lilacs are swelling; I’ve had reports of bud swell on peaches and other fruit trees, especially closer to the Ohio River.

According to the Weather Channel website (http://www.weather.com/weather/ ), our overnight temperatures will be dropping below freezing this week. According to the 10 day forecast for Evansville, we can expect overnight temperatures in the 20s starting Wednesday night, and continuing through Sunday night. The most recent prediction on this site is for a low of 20 degrees on Friday night.

Temperatures this low are going to cause damage to any exposed leaves and blooms. Expect to see daffodil foliage killed back to the ground, along with any other perennial plants that started to sprout. Fortunately, the soil is pretty warm, so the bulbs and perennials themselves shouldn’t be killed: they will sprout back out again, and may even bloom this spring.

Shrubs like azalea, lilac, and shadblow are in a very sensitive stage of development, as are crabapples, peaches, and ornamental cherries. As long as the buds haven’t opened, or at least, not show more than a little bit of a green tip, I expect that freeze damage to the blooms will be minor. If peaches, which are probably the most sensitive of our fruit crops, are still in the swollen bud stage, then a temperature of 18 degrees will only kill about 10% of the blooms…hardly noticeable. But if the peach flowers are showing any pink, then the same 18 degree low will wipe out 90% of the blooms.

Strawberries may be badly hurt. It never really got cold this winter, so the plants never really got into full dormancy. Check your garden: if you see any new green leaves, or (worse yet) any blooms, then a drop in temperature below 28 degrees is going to devastate them. If you still have your straw, plan on covering the plants deeply late afternoon, before the temperature drops. Remove the straw in the morning, after the temperature gets above freezing. Looking at the forecast, we’ll be doing this all week.

I’ve seen roses actually leafing out already. Roses produce their flower buds on new growth, so if some of the new shoots get frozen, the plant will simply sprout some more shoots and go on to bloom later in the season. However, a drop to 20 degrees, as predicted, could do more than blast some leaves and shoots: large portions of the plant could be killed back. It is most important to protect the graft union (a swollen section on the lower trunk, where your pretty rose branches, the scion, are grafted onto a root stock). If the graft union is damaged, then the plant will sprout from the roots, giving you a poor quality “wild rose”, which will look nothing like the plant you bought. Mound the base of the plant with wood chips, shredded leaves, or straw to a depth of 18 - 24 inches.

I don’t think you’ll need to cover your shrubs with sheets, but if you do, be sure to use a cloth sheet, and not a plastic tarp. Heat leaches right through the plastic, and any foliage touching it will be frosted. Don’t lay the sheet over your daffodils – you’ll wind up breaking the stems off. The sheets will only protect your plants down to a temperature of 25 to 26 degrees; much below that, and you may still get injury. If the sheet hangs all the way down to the warm ground, you may be able to withstand a colder overnight temperature as all the warm air is kept around the plant.

BTW: Please DO NOT refer to the cold snap this week as a “late frost.” Our average last frost of the year is the first or second week of April for the southwestern corner of Indiana. It’s SUPPOSED to be this cold!

Good luck!

In the Grow - Q & A

Rosie Lerner, Purdue Extension Consumer Horticulture Specialist

shelf fungi (top) and lichens (bottom)

Q. We are enclosing some pictures that we took of some of our trees, which have been attacked by disease. We were wondering if you could tell us what it is and how to treat it. I'm afraid it will spread to our other trees and eventually kill them. The types of trees are maple, apple, oak and poplar. We appreciate any help you can give us.

A. I have good news and bad news. Your trees have two types of growth showing in these photos. The good news is that neither spread to other healthy trees.

More good news is that the flatter, grey-green growth is a colony of lichens - harmless symbiotic (mutually beneficial) organisms composed of a combination of fungi and either algae or cyanobacteria. Together, they live as one organism and are only using the bark of your tree for anchorage; lichens are not parasites. More information on lichens can be found at http://www.ppdl.purdue.edu/PPDL/expert/Lichens.html.

Some not-so-good news is that the creamy-colored growth that protrudes a bit from the trunk is called shelf fungus and lives on old, usually decaying, trees. While this fungus does not cause disease itself, it is an indication of serious decay problems below and can further weaken the tree. The fungus is less serious than the principal cause or causes of decay. Affected branches can be pruned out, but there's nothing that can be done when the decay is on the main trunk. The tree can continue to live for quite a few more years, but eventually it will need to be removed.

  Norfolk Island pine

Q. I've inherited a distressed Norfolk Island pine. It was in an office, which was very dry, and it had been neglected, even as to its watering. It now is in my living room, and I would like to do what I can to get it back to health. It is sparse from the middle on up. I have removed all of the dead branches. It measures approximately 48 inches from the top of the soil to the top of the branches and measures about 48 inches at its widest point. The pot that it is in is 12x16 inches and does not have any drain holes. It is not full but is very wide. Should I prune the tree? I have attached a picture. What is the best course of care?

A. Unlike many other plants the Norfolk Island pine is not able to replace the gaps in the middle. Any branch that has dropped needles or whole branches that have died will remain bare. So there is no way to prune it that would result in desirable regrowth.

The most immediate need is to repot into a container that allows excess water to drain away from the soil. However, given the bare areas in the middle, you might want to consider either starting over with a new plant or, if you really want to save this particular plant, you might try to root the cut top and discard the bottom. Norfolk Island pine cuttings can only be taken from the top of the central leader stem; cuttings from the lateral branches will not form a new leader.

More information on the care of this plant is at http://www.hort.purdue.edu/ext/norfolkislandpine.html and on how to take cuttings at http://www.hort.purdue.edu/ext/HO-37web.html.

Soil Testing for Lawns

Nicholas Held, Extension Educator, Spencer County

By this time of year, most lawns have seen their last mowing and last fertilization of the season and, with the exception of raking a few remaining leaves, there aren’t too many lawn tasks left to finish.  One task that can still be done is soil testing.  Testing the soil in the fall will allow plenty of time to get the results back and plan any fertilizer applications or other soil amendments before spring. 

Periodic testing of soil will help determine what the soil needs to nourish healthy turf and fertilizer applications should not be made without periodic soil testing.  Soil scientists recommend testing the soil in your lawn every 3 to 5 years.  Soil testing bags and forms are available at Extension Offices throughout Indiana.  

The following are some tips on soil testing and some explanations of soil testing terms:

Taking a Soil Sample

·         Contact your county Cooperative Extension office or soil testing lab for the fee structure, mailing containers, and other information.

·         Using a small shovel or soil probe, sample to a 3-inch depth.

·         Take approximately 10 to 15 samples per lawn and remove thatch and live plant material.

·         Combine the samples to make one composite sample.  Do not mix soils of different texture and color, from areas differing sharply in elevation, or from disturbed sites and undisturbed sites.

·         Air dry the sample before sending.

The Soil Test Report
After processing your soil sample, the soil test lab will send you a soil test report.  The following are usually included in the report:

Soil pH - A soil pH indicates whether the soil is acidic, alkaline, or neutral.  The concentration of soil nutrients will vary depending on the soil pH.  A soil pH below 6.0 indicates an acidic soil and a lime application may be recommended.  DO NOT APPLY LIME UNLESS IT IS RECOMMENDED.  Most Indiana soils under turfgrass do not need liming.

If the soil pH ranges from 6.0 to 7.5, it is unnecessary to adjust the pH.  This is the optimum pH range for turfgrass growth.  For a pH above 7.5 (rarely a problem in this area), there is no practical or economically feasible soil amendment for a lawn.  To compensate for a high pH, increase the annual nitrogen, phosphorus, and potassium applications by 25 percent.     

Phosphorus (P) - The soil test results represent the amount of phosphorus available to the plants from the soil.  Phosphorus deficiencies are rarely observed in established turf in Indiana, except on soils with very high pH.  When establishing or renovating an area, a phosphorus application will help establish seedlings.  A fertilizer high in phosphorus (also called a "starter fertilizer") should be used for this application and should be applied at 1.5 pounds P₂O₅ /1000 ft².

Potassium (K) - The soil test results represent the amount of potassium that is available to the turfgrass plant. Potassium deficiencies are rare in turf in Indiana soils except possibly on coarse-textured, sandy soils. Muriate of potash (0-0-60) can be used to increase soil potassium levels.  Muriate of potash can burn leaf blades, so apply in cool, dry weather and water the area soon after application. 

Cation Exchange Capacity (CEC) - This number represents a measure of your soil's capacity to hold nutrients; the higher the CEC, the more fertile the soil.  It is used by the soil test laboratories in making certain nutrient recommendations for your lawn.  The cation exchange number of an established lawn will not change significantly with time.  In addition, it cannot be adjusted by adding fertilizer or chemicals.

Nitrogen - There is no reliable soil test for nitrogen.  Therefore, other factors should be considered in planning a nitrogen program.  The nitrogen program is the key to a successful turfgrass fertility program.  For more information on nitrogen applications, see Purdue Extension Publication AY-22, Fertilizing Established Lawns.