Below is a list of the best vegetables that grow well in clay soil. Gardening in clay is a bit more challenging than say a fine loam – the good news is that it is quite easy to work clay soil into a loam. While you garden, you build your soil up, and as time goes on, any soil becomes good soil if you know what to do.
What is Clay Soil?
Clay is defined as very fine soil with a particle size of 0,002mm or less that has a plastic nature when wet, and a hard solid nature when dry. Clay soil is generally rich in nutrients, and tends to hold water quite well. Because the soil particles are very small, a lot of the water is actually bonded to the soil – hence about half of the water in clay soil is available to the plants.
Clay soil can be quite difficult to garden in unless you work on it to improve it. It is prone to becoming waterlogged – or, if it gets dry, it gets a crust on the surface, and then if it does rain the water just runs off the surface. In short, unimproved clay soil is just a pain. I know this – my garden is based on clay soil.
How Do We Improve Clay Soil?
My general advice is that if you have clay soil, that is low in organic matter and just poor soil, you will need to make a few quick adjustments to it before you even bother starting to garden. There are plenty of blogs out there that tell you how to “grow vegetables on clay soil”. I suspect many are written by people who have not actually ever done this.
Break the soil. If you are adventurous you can try a pick and shovel for this. I bought myself a rotavator. Mine is a Husqvarna, but this looks like a clone of it. Clay puts a lot of strain on these machines so work slowly and let it break the soil up into a fine tilth. You may have to wet the soil a little with a fine sprinkler for a few days if the clay is really compacted and dry.
This is an incredibly important step – rotavate gypsum into the soil. Gypsum has the effect of sticking clay particles together, this makes them bigger – and it improves drainage, air penetration, the extent to which soil will compact, and many other factors. You can be quite liberal with this – add half a pound per square foot or so, and rotavate it deeply into the soil.
Add pearlite. I am a firm believer in this stuff. It is not too expensive if you buy big bags of it. I would suggest adding a two-inch layer over your clay soil and mixing this into the soil.
Ridge the soil. If you dig the soil into ridges you improve drainage, aeration, and heat transfer. One of the big problems with clay soil is that it is wet and soggy.
This means that plant roots struggle to get going in it. If you make ridges that are at least a foot to two feet high, and ideally three feet across at the base, you can then layer manure, leaves, and other organic matter between the rows. This has the effect of creating compost heat, which warms the soil, and allows you to overcome the “cold clay soil” problem.
You can then also mix the compost that forms into your soil each year, and with time, the compost, plus the soil particle size enhancing effect of gypsum converts your clay to loam. And that is why I have loam in my garden now and had clay a decade ago.
A-List Of Vegetables That Grow Well In Clay Soil
If you follow my soil development tips listed above you can basically grow pretty much any plant in enhanced clay soil! If you do not want to put all that work in, at least dig a bit of compost and manure in the soil and try the following list of my top 10 Vegetables That Grow Well In Clay Soil:
Peas can grow in clay soil. I find that you do need to mix some compost into the soil and grow the peas on ridges of soil. They have bacteria in their roots that can fix atmospheric nitrogen and make fertilizer for the peas – the nitrogen does however have to be able to get to the pea roots. Growing on ridges helps with this.
Carrots can grow in clay soil, but you do need to help them. If you have dense, unbroken clay, the carrots will not be able to penetrate the ground. They will then just grow in a little spiral.
For carrots in heavy clay, you need to mix a bit of fine compost, and ideally follow my instructions earlier on how to build clay soil. If you do not work quite a bit on clay soil first, carrots can be a flop. Again making ridges helps, because the carrots can “drown” if you get heavy rain, so you need to ensure a bit of drainage.
I find that carrots mature slowly in heavy clay, but if you follow my soil fixing steps above, you will get the best-tasting carrots, because clay soil does have a lot of trace element nutrients in it, and the carrots accumulate these.
Tomatoes grow well on clay if you mix a bit of manure into the clay first. Ideally, follow my soil fixing tips above and you will be able to grow tomatoes easily in that soil. If however, you want to quickly get a crop before you put too much effort into fixing the soil, I would suggest making a mound of clay soil, mixing manure and compost into it, and then planting your tomatoes on top of the mound.
Mulch the mound well. Tomatoes can do very well in a clay mound like this, and the taste of tomatoes grown on clay is exceptional.
They grow well in clay soil. You do need to dig the soil over and incorporate compost and manure if possible. Grow them on ridges.
Green beans are one of my favorite crops. I have probably 70 or more different seed types that are cross-pollinating in my garden each year. Keep seeds that did the best to replant each year and your beans become more adapted to the soil you have.
Beans are legumes, like peas, growing them on ridges or mounds allows more Nitrogen to penetrate the soil for the nitrogen-fixing bacteria to make fertilizer for you. I like to grow beans and a pumpkin on a mound when I have clay soil. This means the pumpkin manages soil moisture.
You can water daily once the pumpkin is a few yards long, and it will suck all the water out of the mound, allowing the beans to have “well-drained” soil. As the water is sucked out of the ground by the hungry pumpkin, the nitrogen gas is pulled into the soil where it becomes available to the bacteria in the bean roots.
This is a very easy vegetable to grow in clay soil. Choose an old variety like Ashley. These will benefit from being planted on a mound that has been amended with copious manure and compost.
Mulch the soil well and provide a trellis. Prepare to be sick of cucumbers – it is exciting producing these things for a few weeks, and then you start to get sick of them. Use surplus as a filler in smoothies.
It is a hardy vegetable and grows well in clay soil. You should add lime to the soil. It takes about 75 days for corn to mature. I find that dwarf corn does better in clay. I tend to grow colorful varieties such as something similar to this.
These are also hardy vegetables and grow well in clay soil. They require a lot of water and manure. Be sure to mulch them well, as this prevents clay crusts from forming on the surface.
Lettuce is one of the easiest vegetables to grow. Ideally, choose leaf lettuce as this allows you to harvest a leaf off each plant every two days or so, and then you can harvest a salad every day from a patch of leaf lettuce for a month or two before it flowers. Allow it to flower and it will seed everywhere.
From that point onwards you never need to buy seeds or seedlings – it just comes up in your garden and you can move the seedlings to new places if they come up on a path, etc.
Hubbard squash and pumpkin
These two are heavy-producing plants that you have to grow if you have the space! Ideally, dig a mound of clay that is about two feet high, mix manure into it, and plant the seeds in threes on top of the mound. Once these get going they will suck so much water out of the soil that they create a self-breathing clay soil.
Ideally, plant a few maize seeds and a bean on each maize seed on top of the mound. The squash, maize, and bean symbiosis increases production for all three!
Summary Of Vegetables That Grow Well in Clay Soil
The above list of vegetables that grow well in clay soil is not complete, you can grow many other vegetables that do well in clay soil. You can also add some sandy soil to the clay soil to make it perfect for some vegetables that require lighter soil.
Ideally, follow the advice I gave above on how to build clay soil and then you will eventually be able to grow your plants with little worry at all. Clay soil is a bit of work to get it up to full quality, but once you do, the taste of produce produced on clay soil is an exception. My garden is on light clay, and my parent’s garden is on heavy clay, so we have learned over the years that having raised beds or ridges, lots of organic matter, mulches, and being careful with watering is the trick to a productive clay soil garden.
The fingers that type this article right now, are fed on nutrients from the clay soil garden I have turned into an oasis of productivity in a desert of suburban gardens and lawns.
Read more about 9 Vegetables With Shallow Roots For Your Garden Box
Frequently Asked Questions
What crops grow in clay soil?
Clay soils can be used to grow a wide range of crops. However, a number of conditions must be met. Clay soils are prone to compacting or getting water logged - you need to add organic matter, and ideally mulch to keep the soil from forming crusts. Adding gypsum can assist in improving soil particle size, making the soil better drained.
How do you prepare clay soil for planting vegetables?
I like to break the soil first, then mix gypsum, compost and manure into the soil and then ridge the soil. Grow plants on top of ridges and fill the troughs with sticks and leaves and mulch. With time, mixing this back into the soil results in a loam.
Is clay soil good for planting?
It will depend on how heavy the clay is. You can rework any soil if you add enough organic matter and gypsum and amendments such as pearlite to the soil to improve friability. Once you fix a clay soil I tend to find that it produces the best tasting vegetables due to the high concentration of micronutrients in clay.
How do you start a garden with clay soil?
Break the soil, treat with gypsum, incorportate compost and manure and then ridge the soil and grow your plants on the ridges. Mulch heavily.
Caroline is a gardener who loves to get down to the nitty–gritty of gardening. She proudly proclaims herself as a ‘dirt worshipper‘ and can often be found deep in the garden, covered in soil and singing to her plants. As a self–proclaimed ‘plant whisperer‘, Caroline believes that plants need love and attention just like any other living thing, and she loves to give them both. When she‘s not tending to her garden, you can often find her researching the latest gardening trends, or teaching others how to make their gardens thrive