It all starts with the soil! Here’s how to improve soil drainage

If you want an abundant garden jammed with healthy plants you have to have good drainage. Most  plants will not flourish in heavy, waterlogged soil so the essential ingredient to a good garden is to improve soil drainage. Getting it right is a continuing process. There are no short cuts, it can be hard work to improve soil quality and  takes years. However, if you get the soil right, you will be rewarded with strong, vigorous plants that resist pests and diseases and produce abundantly. You will be considered someone who has ‘green fingers.’

To get those fingers really green here are 8 ways to improve soil drainage:

1. Remove large stones

It may seem obvious but let’s start with the fact that most plants will not grow well if planted on top of large stones. I started my first garden in the lovely village of Stonesfield in Oxfordshire. As the name of the village implies, the ground was full of stones. We tackled the problem by digging up the large stones and raking out as many as possible of the small ones before planting.  If the soil is really bad, an alternative is  to build raised beds and fill with a good quality topsoil compost mix so the plants are above the stones. Often when people move into a brand new property, once they start to dig the garden, they find all sorts of stones and debris buried under a thin layer of topsoil. The only solution is to dig out the debris and sub-soil and incorporate a mix of good quality topsoil and compost.

2. How to improve soil drainage on clay

My current garden lies on a seam of  heavy clay. In my opinion there are worse types of soil because a clay soil will be better at retaining nutrients than for example a sandy soil, however, it does need working and it’s an ongoing process. To help improve the soil drainage, keep adding organic matter, such as well-rotted manure. Do this every year and it will help break down the clay particles. Well-rotted means the manure has been allowed to rot down for at least 6 months. You can buy manure in a garden centre or DIY store, or if you have a stables nearby, ask if you can have some horse manure.  This is the most economical way to get good manure, to make sure that it is well rotted, leave it in a corner of the garden until it no longer smells of ‘horse!’  When planting in clay soil it’s a good idea to add some horticultural grit while planting, especially for those plants that hate getting their ‘feet wet’ in winter (which is most plants!) These  little stones  will eventually wash down into the soil to help with the drainage. Never walk on clay soil when it is very wet, this compresses it and prevents water, air, and oxygen from reaching the roots of plants so, if possible, create paths around the growing areas and use an old plank for walking on.

3. Make your own compost

Add compost to your soil at least once a year to improve the drainage. The most economical and environmentally friendly way to do this is make your own. It’s not hard to do and very rewarding! You can create as many bins as space allows. Even in a small garden you can buy composting bins for a small space. Fill the bins with a mix of green and brown waste. Lawn clippings, annual weeds, plant trimmings and other soft material that rots down. Cardboard, old woollen jumpers, kitchen waste (but not food to attract rats) I even add the contents of my hoover! Get the right balance and you will be rewarded with a crumbly compost that will improve the quality of your soil for free!

 4. Make Leaf Mould

Another free way to improve soil drainage is making leaf mould. Obviously you’ll need to have trees in your garden to do this one, but if you have it’s very easy to make leaf mould. It does not require any special conditions, just collect all the leaves you can gather and put in a wire cage and leave for at least a year. Alternatively, gather the leaves together in black bin bags (I use old compost bags) and leave in a corner to rot down. After about year you will be rewarded with the most excellent, friable, leaf mould full of beneficial nutrients to add to your soil.

5. Use a mulch.

Over the years I’ve used all sorts of mulches (a mulch is a layer spread over the top of the soil) and found that bark chippings are the best. Using bark chippings as a mulch not only improves soil quality but also acts as a weed suppressant and helps prevent moisture loss. Bark chippings will gradually break down, releasing valuable nutrients to feed your plants. I add a layer of bark chippings in the early spring every year after spreading the soil with manure.

6. Green manure as soil improver

If you grow your own vegetables try growing cover crops (also known as green manures) to improve the soil quality in your vegetable bed or allotment. Some can provide food too. Plant a cover crop in the late summer and allow it to remain over winter. It protects the soil from being eroded by severe winter weather, prevent the soil from compacting, and helps reduce weeding. There are various cover crops to try including  kale, clover, ryegrass, radish, turnips, legumes, and peas. In spring turn over the crop and allow it to decompose to increase soil fertility. In the vegetable garden, rotating your crops each year increases the depletion of nutrients and helps improve the soil quality.

7. Encourage Worms!

Worms are a sign of healthy soil so encourage them as much as possible to improve the quality of your soil. Add as much compost as you can to feed earthworms and other microbial life in the soil. The worms will tunnel through the soil improving the aeration and drainage while leaving behind their castings which increases soil fertility. Many of my gardening friends have a ‘wormery’ and turn kitchen waste and small amounts of garden waste into nutrient-rich compost and a concentrated liquid fertiliser. This is not the same as conventional composting. The worms used for composting are not earthworms. Composting worms live in decaying organic matter, whereas earthworms are soil dwellers. They are smaller and darker red than the common earthworm.  Worm compost can be used as a general soil conditioner, just as you would with conventional compost. It’s generally rich in nitrogen and potassium so perfect to improve the quality of soil. The liquid drained from wormeries can be used as a liquid fertiliser on garden plants after diluting with water.

8. Create a woody canopy to improve soil drainage.

If the soil is very wet all year round the year consider planting things that will soak up the water and thrive in the damp conditions.  The red-stemmed dogwood Cornus alba ‘Sibirica’ and the green-stemmed Cornus sericea ‘Flaviramea’ will both grow in heavy, wet soil. They are grown largely for winter interest, the bark on a sunny winter day almost looks as if it’s on fire! Willows are another good choice for wet areas, and although they will need space to thrive they can be kept under control by pollarding back to the base every year once established. The orange-stemmed Salix alba var. vitellina ‘Britzensis’ looks amazing in winter light.

 

If you’re based in Oxfordshire or nearby, get in touch to learn more about our design work as well as our gardening and garden clearance services.