How To Improve Clay Soil For A Vegetable Garden

Clay based soil is a very hard type of soil to garden in where I live. I will be discussing how to improve clay soil for a vegetable garden. Actually I have a loamy clay type of soil at my location. Others within a mile or two from me may have actual clay to deal with. The characteristics of clay soil is poor drainage which promotes root rot and other types of disease. When it rains it packs down and cracks open as it dries.

Other bad things that come with clay soil are poor plant growth and decreased productivity of the plants. Plants roots can not penetrate hard packed clay soil while looking for water and nutrients. This creates a more compact and shallower root system that will not maintain the plants as needed. They will require more frequent waterings and more plant food localized right around the plants.

Their are many ways to improve the soil in your garden if it is mostly clay. One way to beat clay soil is to haul good compost rich soil in and make raised beds, but that is another article in the making.

Soil rich in organic matter
Organic Rich Soil

Composted Manure To Improve Clay Soil

Composted horse or cattle manure is a good resource to help break down clay. As long as the manure has been well composted most of the weed seeds will have been killed by the heat build up in the manure. Horse manure is not supposed to have as many weed seeds in it as cow manure does.

Also chicken, turkey and rabbit manure are good alternatives to the horse and cattle manure. They must also be well composted too as it helps control disease and breaks down the bedding that has been used. Most of their bedding is made up of wood shavings and will contain very few, if any weed seed.

Hardwood Bark Mulch as A Soil Improvement

If you are as fortunate as I am to live in logging country your local sawmill will probably have a pile of bark mulch. The main problem with any kind of wood being used as a soil improvement is that it takes up nitrogen. Extra nitrogen needs to be incorporated into the soil to help break the wood down. Also the extra nitrogen will help maintain the nutrients in the soil.

You can take a soil sample and have it analyzed at your local university extension office to see what your soil needs. See the video below.

Conduct Your Own Soil Test

There are many different types of soil test kits on the market. Here is one that seems to have a lot of sales and a lot of good reviews.

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Luster Leaf 1601 Rapitest Test Kit for Soil pH, Nitrogen, Phosphorous and Potash

This soil test kit has over 2000 reviews and a 4 out of 5 rating. It tests the soil PH, Nitrogen, Phosphorus and Potash. It does not give you any idea of the organic matter in your soil.

The easy way to test your organic matter in clay soil is to do the ball and squeeze test. When the soil is moist, take a handful and form it into a ball. Squeeze the ball and see what happens. If the ball compacts into a tighter ball then you need more organic matter in your soil. If there is plenty of organic matter there the ball will fall apart in your hands.

How To Improve Clay Soil For A Vegetable Garden With Straw

Straw that you use to mulch your garden with will go a long ways in helping your soil. As with the wood mulch you should add more nitrogen to your soil to help with the breakdown of the straw. Straw will also rob your soil of nitrogen just as wood mulch will.

The best way to use straw is to mulch your garden with it this year. After your garden is done and you are cleaning up leave the straw alone. Either till it into the soil in the fall or wait and let it deteriorate over the winter and till it in the next spring.

Leaves To Help Maintain Your Soil

Have you ever been out in the woods and pulled the leaves back from a spot on the ground? What you will find is some of the richest darkest soil around.

Leaves decompose and make the best soil available. Instead of burning your leaves in the fall spread them on your garden. I run over them with the lawn mower to help start the breakdown process.

Till them into your soil or if you are a no-till fan just leave them there and plant through them. Throw a little extra nitrogen on them to help speed the decomposing process and help conserve your garden’s nutrient system.

Cottonseed Meal Soil Amendment And Plant Food

Cotton seed meal is a good organic fertilizer and a very good soil amendment. Spread the cottonseed meal down the row around an inch thick. It will feed your plants and also add organic matter to the soil at the same time.

Cottonseed meal varies in formulation slightly, but is generally made up of 7% nitrogen, 3% phosphorus, and 2% potash. Cottonseed meal feeds nitrogen, potash, phosphorus and other minor nutrients over an extended period of time, promoting vigorous growth of your garden vegetables.

Cover Crops Or Green Manures

Another traditional source of organic matter and nutrients is growing plants in your garden and then plowing them into the soil to decay and release nutrients for the next crop. Crops grown to add nutrients to the soil are called green manures.

Some plants are selected as green manures, because of efficient, deep root systems that bring nutrients up to the soil surface, others because they are hardy or more tolerant of environmental stresses.

When nitrogen is limiting, the most important green manures are plants that are able to capture nitrogen from the air and make it available in the soil. These crops are known as legumes and in the garden include clover, alfalfa, or vetch.

Clover For Green Manure
Clover For Green Manure

How Green Manure Plants Work

These plants have what I call nodules on their root system that creates nitrogen in a form the plants can use. The plants can grow larger with the nitrogen and provide more sugars.

This nitrogen can be used by other plants as the original nitrogen fixing plant decays. Since these crops need to be productive for a year or more, a part of the garden is taken out of production of the normal crops.

Another option is planting the aisle ways between crops to a clover that can be mowed and walked on. If there is not room on or in the garden, green manures can be grown elsewhere. Top growth from these plants can be harvested and added to the compost pile.

Conclusion On How To Improve Clay Soil For A Vegetable Garden

I forgot about green sand and sharp sand, they are not available in my area and I always forget to mention them.

Note that adding regular sand or masonry sand will turn your clay soil into the next thing to concrete. It will do more harm than good.

Vermiculite and perlite are also very good at loosening up the soil. They can not be found in bulk quantities as easily as the others that I mentioned and can be quite expensive. They would be good in a very small garden or in raised beds though, if that is what you are needing them for.

There are many other ways to improve clay soil for a vegetable garden that I have left out of this article. Do you have your own preferred way to add organic matter to your garden soil? If you do, let me know in the comments below. I would be happy to hear from fellow gardeners. Also I am always ready to learn and try new things.

Read my article on how to grow pole beans.

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