Every gardener faces a range of common garden soil problems. Depending on your region, you may face stubborn, compacted soil or a spot in your yard with waterlogged soil. You may have been overzealous and tilled too much, or prepared your soil incorrectly. The Anxious Gardener’s Book of Answers(Timber Press, 2012) identifies the 100 most common gardening mistakes and gives gardeners the techniques to prevent them. This gardening guide tackles every kind of gardening disaster, whether it has to do with plants, tools and techniques, or general care and maintenance. Learn solutions for a variety of garden soil problems in this excerpt taken from the chapter “Soil: Respect and Work With Your Garden’s Foundation, and Avoid Many Heartaches.”
Trying to Garden in Compacted Garden Soil
You might have suspected something was amiss when you dug to install new plants, and the shovel or trowel had a hard time penetrating. Or you might suspect compacted soil if water runs right off or sinks in slowly, indicating there are few available air spaces, either because of parched ground or extremely saturated soil. Neither environment is good for most plants. Their roots will struggle for moisture, oxygen, and nutrients, and will show their distress aboveground by slumping, failing to produce new growth or flowers or fruit, browning and drying, and eventually keeling over.
The Right Way to Do It
Some parts of your yard are inevitably going to have compacted soil, unless you are willing and able to make necessary changes to improve or shield them. Trafficked areas, such as paths, always get beaten down as people and pets repeatedly walk over them, but frequent passages by a garden cart, a wheelbarrow, bicycles, and small tractors will also contribute to the problem. A location where heavy objects, such as cars and trash bins, are kept is bound to have dense, compacted, unfriendly soil.
The answer is easy: designate some areas for traffic, and others for plants. And the obvious corollary? Don’t plant in compacted soil. If you’d like to plant an area later but need to use it or walk over it for a while, lay down and travel over boards, which will redistribute your weight more evenly and tend to mitigate soil compaction.
If I Goofed, Can I Fix It?
Plant rescue may be possible. Remove the struggling plants, replant them in a more hospitable location, and hope they recover and begin to thrive in their new home.
Alternatively, remove the beleaguered plants temporarily, loosen the soil and mix in some good decomposed organic matter to improve soil structure and fertility, and return them to these improved growing conditions. Rope, fence off, or define the area with edging, route traffic around or away from the area, or otherwise prevent future compaction.
Not Preparing the Soil Before Planting
You’ve done everything else right–chosen a decent-quality plant, provided it with a sunny or shady spot as needed, planted it with care, watered and tended it. And yet, in a few days or weeks, the plant looks terrible or simply quits and dies.
There is no guarantee that native soil is any good. It could be compacted or gritty. It might be contaminated with road salt, motor oil, or other environmental pollutants. It may simply be depleted or infertile. No matter the reason, a new plant cannot successfully send its roots into lousy soil and get the nourishment it needs to grow and prosper.
The Right Way to Do It
Make it your standard practice to improve soil before adding any plant at any time. Most popular garden plants like well-drained, moderately organic soil, which has a rich, crumbly texture and is dark in color. To get it from any other state to something resembling this ideal, add organic matter such as compost, bagged dehydrated cow manure, or chopped-up fall leaves.
Dig down to a depth of 6 to 8 inches, the extent of most plants’ root systems. Go deeper if installing a bigger plant. Mix in the organic matter well–like cake batter, you’ll have to determine the best recipe. Add more in very bad soil, less in soil that appears halfway decent. If the native soil seems truly awful, dig it out by making a hole or trench, and replace it altogether.
Only now should you add a new plant and follow through with good care. Continue adding organic matter in the fall and again the following spring. Soil and plants consume organic matter, so this becomes an ongoing, nurturing practice.
If I Goofed, Can I Fix It?
If a plant put into bad soil is still alive, dig it out and set it aside, either in a pot of soil mix or with a damp cloth over its roots to keep them from dehydrating. Then improve its hole or bed with organic matter as described, replant it, water and care for it, and hope you intervened in time.
What Else?
Sometimes amending is not necessary and can even cause harm. A tree or native plant tends to do best in native ground. A single new perennial, or two, may do just fine with a little compost added to the planting hole rather than a wholesale upgrade of the entire bed. (Vegetable gardens, however, almost always need improved soil.)
Not Knowing What Your Soil Is Like
Some plants prefer certain soils. If you plant lavender in moist, rich, acidic soil, it will flower poorly, produce weak foliage, and generally sulk, for it wants well-drained, slightly alkaline ground. Conversely, if you give a camellia a sandy, dry site, the shallow roots cannot access the water and nutrients they need to supply to the plant. The leaves and the flower petals will dry out, and the plant will decline and die.
The Right Way to Do It
Never add a plant to your yard without knowing if you have the right soil type to support it. Yes, you can supply special soil for a special plant, but it is so much easier to make a good match at the beginning.
If you don’t know what kind of soil you have (rich or lean, moist or dry, alkaline or acidic), it’s not hard to find out: conduct a soil test. You can get a formal kit at a garden center or via the Cooperative Extension Service; these kits come with complete instructions and involve digging up soil samples from various parts of your yard and sending them to a lab for analysis. Or you can do less precise identification. The plants prospering there now, including weeds and ones you have not planted, can provide clues. Look up what they prefer. Alternatively, ask a professional landscaper to recommend soil improvements as well as plants that ought to do well in your yard. If you don’t want to fuss, your best bet is native plants, which are already adapted to local soils and climate. Ask for them at your local garden center.
If I Goofed, Can I Fix It?
If a plant is unhappy, take it out and grow it in a pot of appropriate soil, give it away, or toss it on the compost pile. Then plant something that likes the soil you already have.
Digging or Tilling Too Much
Turning over the soil every spring is a popular garden ritual, so entrenched that few gardeners ever question it. There is something satisfying about breaking ground and feeling your shovel slice into the earth. But it’s also hard work, especially tough on your back, and it can be distressing to watch what often follows–a weed explosion. Weed seeds that had been dozing underground are now exposed to air and light, and once stirred, they wake up and grow.
Ritual spring digging also delays planting, because you cannot dig until the soil dries out a bit or it will be compacted, not to mention a messy job. Furthermore, soil bacteria and fungi burst into activity after tilling, consuming organic matter. You want them to settle down, which can take a few weeks, before adding any seeds or plants to the area.
The Right Way to Do It
Delay digging until later in the spring, when the soil is not mucky. The object of digging should be to get rid of existing vegetation or to turn under a deliberately planted cover crop. Another benefit is aerating compacted soil so new seeds and roots can become established. Mulch the area immediately after digging to discourage weeds and conserve soil moisture, and replenish as needed when you finally plant.
Some gardeners believe in skipping digging altogether and following nature’s way of letting humus settle on and into the ground over time. They note that digging disrupts natural soil layers and drainage capability, as overdug soil drains too quickly. If your garden soil is in good shape to begin with, try taking a year off from ritual spring digging, but don’t forget to mulch.
If I Goofed, Can I Fix It?
Let the ground rest and recover. Don’t plant anything right away, but mulch with organic matter, such as compost or chopped-up leaves, to smother weeds. Later in the season, gently scoot the mulch aside, add some organic matter to the soil, then try planting.
Gardening in Contaminated or Bad Soil
Perhaps you inherited tainted soil from a previous occupant, or someone in your household has rendered an area toxic for plants. They will struggle and die, or you will be left wondering what is wrong or, if the crops are edible, whether they are safe to eat. Among the toxins that are cause for concern are: motor oil and other petroleum products; cleaning solutions, especially bleach; pesticides, including rat poison and flea killers; and lead, usually from paint that has flaked off an old building or fence.
Pressure-treated lumber, often used for garden structures and projects, contains chemicals (including arsenic and copper) that leach into garden soil over time. Don’t grow vegetables or fruits close to this wood.
The Right Way to Do It
Never deliberately plant anything in a contaminated or suspect area. Don’t eat food crops that appear to be growing in such a spot. To identify the scope and seriousness of the contamination, conduct a soil test. Your local Cooperative Extension Service will have kits and information, and can make recommendations or suggest remedies. If you or someone in your household needs to discard a toxic substance safely, your municipality’s solid-waste program can advise you or even take it off your hands. Don’t get in the habit of dumping in your own yard, behind the garage, or in an unused or overgrown area.
If I Goofed, Can I Fix It?
If the dumping has already occurred, stop using the area as a place to grow anything unless or until it is cleaned up. Cover it over or block access to it. Cleanup can be as simple as diluting the area with hose water and as ambitious as digging up a wide area of bad soil and carting it to a disposal site. First identify the toxin, then get advice from your municipality’s solid-waste program, as you may not be able to handle it on your own. In the meantime, perhaps you can pretty up the area by placing potted plants on-site or growing plants in raised beds bordered by stones or untreated lumber.
Struggling with Waterlogged Soil
Maybe it’s obvious that a certain bed or corner of the yard is soggy because of standing water or moisture-loving weeds like watercress or sedges. You tear out these unwanted plants and try a few colorful flowers, but they don’t prosper or they succumb to rot.
It’s also common to find out the hard way that an area has sodden soil. You plant some bulbs, or even a tough perennial like Shasta daisy, and a wet, cold winter reveals that the area is low and water is draining into it and sitting there. The plants you introduced then fail because of the lousy drainage.
The Right Way to Do It
You have two choices. You can try to keep the moisture away, diverting incoming water or creating pebble-filled drainage basins or trenches in the vicinity. While you’re at it, dig in some organic matter to lighten the soil’s texture and provide a little oxygen and space for the root systems of plants you want to grow there.
If this seems like too much trouble, or if your remedial efforts don’t succeed, your best bet is to plant the area with moisture-loving plants. Among annuals, this includes angelonia, impatiens, and even pansies. Perennials that relish damp ground include bee balm, cardinal flower, and crocosmia. If the area is truly sodden for much of the growing season, try various irises, mint, or the colorful, ground-covering chameleon plant (Houttuynia cordata). Do a little research or ask for more ideas at your favorite nursery–there are many fine choices. Just bear in mind that plants known to relish damp growing conditions can and will take over an area. At least they will be ones you want, though, and not unwelcome weeds.
If I Goofed, Can I Fix It?
If you planted unsuitable plants in a damp area, don’t fight a losing battle. Take them out while they are still alive and give them a more appropriate home elsewhere in your garden.
This excerpt has been reprinted with permission from The Anxious Gardener’s Book of Answers, published by Timber Press, 2012.