How to Improve Clay Soil Drainage

Nutrient-rich and high-quality soil is the key to any great gardens. But, what if your soil is heavily impacted in summer yet sticky in winter? If you know how to improve clay soil drainage, though, there is no need to worry about its poor aeration.

How To Improve Clay Soil?

Dig Over Your Soil In Autumn

digging soil

To boost your flowers and veggies’ growth, soil digging is essential. If your crop growing soils are at low-quality or its quality degrades over time, you should add organic matter at the same time as you aerate the earth.

All you have to do is to turn over the bare spots in your garden with a garden fork. However, instead of breaking up the bigger clods for a finer tilth for planting, you should let the lumps intact encourage more water to penetrate and more oxygen to get to your plants’ roots.

Let the cold and frosty winter weather naturally break up the ground and give you a more suitable tilth!

However, those wanting to grow any hungry crops should do some double digging. As this method will not only bring cabbage loopers or corn earworms to the surfaces but also incorporate some well-rotted manure or a full compost heap, it is such an effective way to add much fertility and improve drainage.

To make the double digging step less difficult, you’d better divide your vegetable gardens into several 8 x 4 beds.

Use Winter Cover Crops

Winter cover crop

Winter cover crop is among the most conventional methods as it not only improves its drainage but also ensures soil enrichment.

Cover crops that are grown on clay soil will be tilled back into the soil to add nitrogen and enhance its nutrients or organic matter content before running to seed extremely compacted soil.

Some of the most common cover crops to grow are winter grains such as grasses, fava beans, clovers, winter wheat, and legumes, which protect your fallow soil from erosion through the cold weather while developing their huge root systems.

Decide which variety to grow based on specific needs of your clay soil and when you plan to plant it!

If you want to add organic material and nodules of nitrogen to improve your clay soil drainage, it is a good idea to grow a hardy legume winter cover crop alongside a non-legume one to take advantage of both within only one growing season.

If it’s high time to grow winter peas or hairy vetch but your greens are still producing, you can sow the cover crops in the space between rows. That way, the soil microbes can break the organic materials into humus required by your plants.

Add Mulch To Your Soil

add mulch to soil

As clay shrinks and cracks gradually appear right after it dries out, it is a good idea to add organic amendments in late spring to prevent clay soil inadequate drainage.

From shredded or chopped leaves and grass clippings to coffee grounds and straw, mulch adds organic matter. Though it takes time for mulching to work, if you do it right, it can act as a nutritious conditioner, thus doing miracles to your property.

Mulch excels at not only holding onto water in the soil, which is beneficial to plantings and delicate root systems but also protecting your soil from getting compacted, which encourages greens to thrive.

Slowly dig a hole into your soil’s top or let the worms or any other garden insects work in return. However, since organic matter decomposes and faster mixes with the soil, you have to keep adding an adequate layer of mulch to discourage the unexpected weeds from growing around your plants.

Even though wood chips or bark shreds break down and decompose slowly, they will steal nitrogen from your plants. So, before adding mulch to your soil, you should sprinkle on a nitrogen-only fertilizer or a nitrogen-rich blend such as dry cottonseed meal, pelleted chicken manure, blood meal, fish emulsion, or urea.

Plant Your Vegetables When The Weather Gets Warmer In Spring

plant vegetables in warm weather

Fall planting can result in high losses as in winter clay is slimy and heavy while the soil drying into chunky slabs remains cold.

Of course, no gardeners can devote 365 days a year to improving clay soil. However, at the very least, they put much effort into applying soil amendments in the autumn before planting their favorite vegetables in the spring, once they see the first sign of buds breaking.

Lay Down A French Drainage System

No article on how to improve clay soil drainage can be complete without mentioning an underground drain. And among various solutions for moving water downhill, a French drain, which is essentially a herringbone-like ditch filled with gravel and rubble and replacing the topsoil, is the most popular one.

Another ideal underground solution for yard drainage issues found in hard sub-layers and compacted soil is a drainage well which allows and encourages the water everywhere to run downhill after rainfall.

To lay down a French drainage system, you have to dig a trench first. Though the trench’s sizes vary, the most common ones that can satisfy most gardeners’ needs are 8 to 12 inches in depth and 5 to 6 inches at width.

Since 1:100 is the correct level between the ending point of the lower elevation and the higher starting point, be sure to precisely measure the slope of the virgin land to that level to allow water everywhere to drain away.

Dig Large-sized Holes When Planting

Dig Large-sized Holes When Planting

The exact depth of a hole varies according to the sizes of the tree trunk and root ball, but, ideally, digging a hole approximately 2x the root ball’s size is always the best bet. And to improve drainage, you can use a fork to break up the hole’s bottom.

Drill Through A Solid Clay Layer

For more serious drainage issues found in a 2- or 3-inch clay layer soil, gardeners have to drill or dig or even double bug to keep it healthy.


Now you have finished reading our instruction on “How to improve clay soil drainage” it’s high time to transform your landscape into what you have been dreaming about.

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