Tag Archives: soil

Garden Advice

Improving Heavy Clay Soils

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Gardeners rarely begin their journey with a plot of perfect soil, but it’s something we all dream about. In the Southeast, many gardeners have to work with heavy clay soils. While clay soil is rich in minerals and many nutrients, it’s prone to compaction, doesn’t drain well in wet weather, and doesn’t hold water well during droughts. Growing certain root crops like large carrot varieties can be especially tough.

Clay soils are a great foundation to improve on. Here are a few organic methods to improve your heavy clay soil. 

Practice No-Till (or minimal-till) Agriculture

It may sound counterintuitive, but tilling can make clay soils worse. Tilling increases soil compaction and kills beneficial fungi and micro-organisms. 

Cover Crops

Cover crops add nutrients and organic matter to the soil. Great choices for improving clay soils include buckwheat, clover, and wheat. Clover has the benefit of being a nitrogen-fixing legume, meaning that through a symbiotic relationship with bacteria, it captures nitrogen from the air and adds it to the soil.

You may also want to mix in large or deep-rooted cover crops like daikon radishes, lava beans, and alfalfa. These crops help break up compacted soil and create channels for air and water as their roots decompose.

Chop & Drop

You can also use a method commonly used by permaculturalists called “chop and drop.” This method involves growing crops like comfrey, pigeon peas, moringa, sun hemp, and sorghum. These crops are chopped and dropped on the soil to decompose. Comfrey is a popular choice for this in perennial gardens and fruit tree guilds.

Broadfork

Broadforking your soil is a great way to loosen soil without disturbing the layers or structure. It helps mitigate compaction and preserve beneficial organisms and fungi in the soil. 

Create Permanent Beds

Even just walking on your garden soil can cause severe compaction. Creating permanent beds that you don’t till, step on, or use machinery will help make light, fluffy soil. 

Use Terraces or Swales

If your property has heavy clay soil and a slope, you’ll probably deal with water issues. Planting in rows or terraces that are perpendicular to the slope of the land will help slow down the water in your garden and reduce erosion issues. Swales built on contours take this further and are a great way to catch large amounts of rainwater, allowing your plants to access it slowly, even on significant slopes. 

Spread Compost

Finished compost is the quickest way to beef up the organic matter in your soil. Adding a couple of inches of compost to each bed adds nutrients, improves water retention and drainage, and lightens the soil.

Use Mulch

Mulch helps block weeds, hold moisture, and keep soil temperatures cool. It also adds a lot of organic matter to your soil as it decomposes. Any organic mulch can help improve your clay soils, including straw, leaves, grass clippings, woodchips, and hay. Keep in mind that hay tends to have a lot of weed seeds.

Grow Varieties Adapted to Heavy Clay Soils

Improving clay soils isn’t something that happens overnight, especially in large gardens. If you’re planting in a garden with heavy clay soils this year, try some varieties that are adapted to these conditions.

  • Chantey Red Core Carrots
    This blocky, broad-shouldered variety with a blunt tip is well-suited to growing in clay. It was introduced from France in the 1800s.
  • Danvers 126 Carrots
    These carrots taper to a blunt point and are especially suited to growing in clay soil. The strong tops aid harvesting.
  • Everona Large Green Tomatillo
    These plants produce large, tasty tomatillos and thrive even in heavy clay soil and drought.  Seed collected by Barbara Rosholdt from tomatillos planted by Mexican workers at the Everona sheep dairy near Unionville, VA. Introduced in 2008 by SESE.
  • McCormack’s Blue Dent
    This beautiful dent corn makes delicious light blue flour and is especially suited to the eastern U.S., clay soils, and drought-prone areas. Introduced in 1994 by SESE. Bred by Dr. Jeff McCormack from a cross between Hickory King and an unnamed heirloom blue dent.
  • Oxheart Carrots
    A good carrot choice for shallow or heavy clay soils that most carrots don’t like. Dating to 1884, this variety produces thick, sweet “oxheart”-shaped carrots, 5-6 in. long and 3-4 in. wide, weighing up to a pound!
  • Pike Muskmelon
    Bred specially for growing in unirrigated clay soil, this vigorous melon has outstanding flavor and good disease-resistant. Introduced in 1935, Aaron Pike of Pike & Young Seeds; seedstock supplied to SESE by Aaron Pike’s niece.
  • Tennessee Red Valencia Peanuts
    This pre-1930 produces rich, sweet peanuts with red skins. It’s easy to grow without hilling, even in clay soils.
  • Texas Gourdseed Corn
    Originally brought to south Texas by German farmers who migrated from Appalachia during the late 19th century, this variety withstands drought and does well in clay soil. In south Texas, this is considered to be the best choice for tortilla flour.
  • Turga Parsnip
    This Hungarian heirloom produces short, stout roots that are good for heavy clay soils.
  • Southern Peas (Cowpeas)
    These productive peas are well-adapted to poor soils and drought. We carry 16 varieties at SESE.
Garden Advice

10 Easy Ways to Improve Your Soil

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Want healthy plants? Start by building healthy soil. Your soil health can affect your plant’s productivity, disease and pest resistance, and more. Use these ten strategies to improve your soil and build a healthier, more productive garden.

1. Start composting.

Compost enriches the soil and adds structure and beneficial fungi and bacteria. It’s an excellent amendment for any garden and easy to make yourself. Check out our post, Black Gold: Making Compost, for easy directions to get started in your backyard.

Those without yards can consider vermicomposting or check with community gardens or city compost facilities to bring kitchen scraps to and access aged compost.

2. Grow cover crops.

Cover crops are not just for big farms! Cover crops help improve the soil in many ways. Some are “nitrogen fixers” like clover and vetch and add nitrogen to the soil as they grow; other crops like buckwheat help quickly build up organic matter and make excellent mulch.

All cover crops are a good way to cover the soil. They shade it holding in moisture, provide habitat for beneficial insects and pollinators, and their roots hold the soil preventing erosion.

You can read more about using cover crops in your garden here.

3. Get a soil test.

Testing your soil can help you make the best choices for your garden, saving you time and money. You’ll learn what nutrients may be missing and whether you should amend your soil’s pH. Check out Understanding Soil Tests for a more in-depth explanation.

You can purchase at-home soil tests at most garden centers or send your soil to be tested. Many universities and state and county extension services offer very affordable soil testing.

4. Understand the soil food web.

The soil food web is similar to a “food chain” but is non-linear. It’s made up of plants, animals, and all the organisms in the soil from visible insects and fungus to microscopic bacteria. A healthy soil food web is key to a healthy garden and ecosystem. Learn more by reading our post, The Soil Food Web.

5. Reduce erosion.

Not everyone is blessed with a large, perfectly flat garden site. Even if you are, wind can still wreak havoc on exposed soil. Don’t lose soil to the effects of wind and water.

If you live in a windy area, utilize windbreaks. These can be fencing, shrubs, or trees. Even young shrubs and trees can make a surprising difference.

To prevent water erosion, you should try to keep your soil covered. Use cover crops whenever possible and keep the soil around plants mulched. Permanent pathways with a cover crop like clover are ideal.

If your property is sloped, look into permaculture methods like planting on contour and building swales. These can help you stop erosion and collect water for your plants!

6. Provide habitat for beneficial insects.

When people hear beneficial insects, they often think of bees, butterflies, and other pollinators. While you should strive to help these species, there are many more that also play key roles in keeping your garden healthy. These include many predatory species such as wasps, beetles, and mantises.

You can support beneficial insects in many ways. Using cover crops and mulch, as I mentioned above, helps provide habitat as does planting native species and leaving dead material in your garden (unless it has a pest or disease issue). You can also create your own habitat by building an insect hotel.  Of course, it’s also important to avoid using pesticides. Even organic pesticides can spell doom for beneficial insects as they usually affect more than one species. 

7. Use mulch.

I’ve mentioned mulch a couple of times now, but it’s incredibly helpful in the garden. It helps to block weeds, keep the soil cool and moist (or warm in the winter), and provides structure and organic matter as it breaks down.

Check our post, Mulch Ado…, to learn more about why mulch is important and how we use it at SESE.

8. Rotate your crops.

Whether you have an acre in garden or just a tiny little plot, you should rotate your crops. Rotating crops prevents pests and diseases from building up the soil where you grow a particular plant. It also helps to reduce nutrient depletion. One year you grow heavy feeders like tomatoes or corn, and the next, you grow nitrogen fixers like beans and peas or a cover crop.

Need advice? See Planning Crop Rotation by Plant Family.

9. Amend your soil.

As you’ll learn from your soil test, it is sometimes necessary to add amendments to your soil. These amendments can be used to change the soil’s pH like lime, wood ash, or peat moss. Other amendments allow you to add the macro and micronutrients that are necessary for plant growth. These include manure, compost, eggshells, greensand, and fertilizer.

Learn more about amendments and common nutrient deficiencies in plants here.

10. Reduce or eliminate tilling.

Rototilling may seem like a crucial part of gardening, but many farmers, gardeners, and scientists have discovered that it’s possible to grow a more productive and more environmentally friendly garden by ditching the tiller.

Going no-till reduces compaction and keeps the soil structure intact. It allows you to use plant and cover crop residue as mulch that will decompose as it would in a natural ecosystem. It also allows beneficial bacteria, insects, and fungi to thrive in the soil. 

Follow these tips to build healthy soil in your garden.

Garden Advice

Common Nutrient Deficiencies in Plants

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Spotting nutrient deficiencies in your plants can be challenging, especially if you’re new to gardening. Here are what a few common deficiencies look like and how to correct them.

Soil Nutrients

Nutrients in the soil can be divided into two categories macronutrients and micronutrients/trace minerals.

The first category, macronutrients, comprises primary nutrients nitrogen, phosphorus, and potassium and secondary nutrients sulfur, magnesium, and calcium. If you think your plant has a nutrient deficiency, these are the likely culprits.

The second category, known as micronutrients or trace minerals, includes boron, chlorine, copper, iron, manganese, molybdenum, and zinc. While these are still important to plant health, they’re needed in such small quantities that it’s less likely your plant is deficient in one of these micronutrients.

You can read more detailed descriptions of what all of these nutrients do in our post, Understanding Soil Tests.

Nitrogen Deficiency

A nitrogen-deficient plant will grow slowly and lack vigor. The leaves may turn pale and yellow before dropping off, with the oldest leaves dropping first.

Note that it’s easy to overdo it when adding nitrogen, especially if you’re using chemical fertilizer. Adding too much nitrogen will cause lush, dark green foliar growth at the expense of fruit and flower production.

There are many ways to add nitrogen to your soil. While you shouldn’t directly apply it to plants, animal manure is a good choice if you have access to it. Compost will also add some nitrogen, or you can add seaweed or kelp meal, fish emulsion, bone meal, coffee grounds, soybean meal, or cottonseed meal. Using legume cover crops also helps to increase your soil’s nitrogen levels.

Phosphorus Deficiency

A plant that is deficient in phosphorus will also lack vigor and may be stunted. It might drop fruit before it’s ripe or not produce fruit at all. The lower leaves may appear red or purple.

You can add phosphorus to your soil using rock phosphate, greensand, compost, or bonemeal.

Potassium Deficiency

Potassium deficiency will probably be most apparent in your plant’s leaves, which may be mottled or curled or have brown edges. The plants will also be weak and have stunted root growth. They will likely be more susceptible to disease and pest issues.

Good potassium sources include manure, compost, seaweed or kelp meal, potash, granite dust, greensand, and wood ashes.

Sulfur Deficiency

While sulfur is a macronutrient, a sulfur deficiency is much less common. Signs include stunted growth and pale, yellow leaves.

Add sulfur with gypsum, compost, or sulfur.

Magnesium Deficiency

If your plant is deficient in magnesium, you may notice poor flower and fruit production, stunted growth, and dropping leaves. Leaves may also appear mottled with yellow/white patches or purple/brown patches between the leaf veins.

To correct a magnesium deficiency, add limestone, manure, compost, or greensand.

Calcium Deficiency

Calcium deficient plants may die back or have buds that die. Their leaves will likely appear burnt, curling, or have necrotic leaf margins. You may also notice issues like blossom end rot and other signs of tissue necrosis.

Use oyster shells, eggshells, limestone, gypsum, or fishmeal to add calcium to your soil.

Notice how similar a lot of these symptoms are?

If you’re having problems with nutrient deficiencies, the best advice is always to get your soil tested. It isn’t complicated or expensive and will tell you precisely what you need.

It will also tell you what your soil’s pH is. Soil pH can affect plants’ nutrient uptake and may cause deficiencies even if your soil is otherwise fine.

If your soil test comes out fine, your plants may be struggling due to over or underwatering or disease issues.

How do I prevent deficiencies?

The first step you should take is to develop a garden rotation plan that includes cover crops. They’re excellent for preventing erosion and adding nutrients to your soil.

Yearly applications of good quality compost can provide a wide range of nutrients to your soil.