Composting Techniques: How to Compost In-Situ

, written by Benedict Vanheems gb flag

Compost pit

At the end of the growing season, piles of cleared crops are a common sight. But what to do with them all? You could add this material to an existing compost heap, but an alternative is to simply leave it – right there on the ground. Called ‘in-situ composting’, it's a fantastic way to build the soil for your crops next year.

Composting in-situ is a great way to cope with lots of spent crops or sudden gluts of kitchen waste, for example when processing fruits and vegetables for winter storage. Composting directly on or in the ground can divert organic material away from overflowing compost bins, while directly improving the ground for next year’s crops.

Composting on the Soil Surface

Finer material such as annual weeds, carrot tops and vegetable peelings decompose relatively fast. You can simply lay this material on the soil surface before covering it over with a thin layer of well-rotted garden compost or manure. This is a simple but effective way to supplement traditional end-of-season applications of organic matter. By spring the material should have rotted down into the ground, leaving behind a beautifully rich top layer of soil ready for sowing or planting into.

Composting in Trenches

Compost ingredients can also be buried in trenches to improve the nutrient content and moisture-holding capacity of soil.

Simply dig out a trench about one foot (30cm) deep. Compost trenches are commonly prepared for vegetables like climbing beans that are grown in rows – the rich, moisture-retentive soil left behind will ensure plenty of produce over the cropping period.

Trench composting

With the trench dug, simply fill it up with your compost ingredients. Suitable ingredients include annual weeds that haven't flowered, grass clippings, the chopped up remains of spent crops, and kitchen waste such as apple cores or vegetable peelings. Fill to at least four inches (10cm) deep, then cover over with a layer of leaves or grass clippings. Fill the remainder of the trench with the excavated soil.

If you plan to plant a row of crops directly on top of the trench and need to locate it in spring, simply mark the position of each end so you can easily find it in a few months’ time.

Composting in Pits

Compost pits use the same principle as trenches. Dig a hole, fill it with your organic waste and cover with a topping of grass clippings or leaves. You can space multiple compost pits in close proximity, creating pockets of nutrient-rich material that will feed the microbes and worms in the surrounding soil.

Healthy courgette plant growing strongly

Compost pits create nutrient-rich and moisture-retentive reservoirs which are great for thirsty and hungry plants such as courgettes, squash and tomatoes. Plant directly on top of pits that were made in the autumn, or dig and fill fresh pits in spring then set one or more plants immediately next to or encircling each pit. As the material rots down it will feed the soil to encourage healthy, resilient growth and bumper yields.

As you can see, composting in situ offers a convenient way to process all that nutrient-rich organic matter back into the ground. It’s easy to do and next year’s crops will love you for it! As always, please share your experiences of composting in this way by dropping us a comment below.

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Comments

 
"I have a question about in-situ composting and pests. I believe there are two primary reasons for rotating crops. 1) nutrient depletion and 2) pests. If pests are attracted to certain vegetables, then isn't composting the vegetables straight into the soil going to spread the pests? Thanks for straightening me out."
Louie on Saturday 21 November 2015
"Hi Louie. You certainly have a point there. Many diseases such as mildew, which you often get on squashes/zucchini/courgettes by the end of summer won't survive the winter. Most problems you don't really need to worry about, especially if you have good hard frosts where you are. The material will break down and any pests and diseases will usually be killed off. However, it may be prudent NOT to spread material from blight-affected crops on the soil surface - late blight, potato blight, tomato blight etc. It is unlikely to survive to the following year, but best to be safe."
Ben Vanheems on Tuesday 24 November 2015
"Hi Ben, I live in Atlanta, Georgia and I appreciate the tips on the pit in-situ composting. I tend to have a lot of kitchen scraps and if I can put them to work in the garden before waiting on my main compost to mature, that's great! I can also target the places where I plan to plant my higher nutrient needs plants. Digging a pit sounds much less daunting than digging a trench in the hard Georgia clay."
Shelby on Saturday 2 January 2016
"Hi Shelby. Glad the tips have come in handy. It should certainly help you to target soil improvements where needed."
Ben Vanheems on Monday 4 January 2016
"Great article with nice content.Thanks for wonderful post."
Direct Compost on Tuesday 29 March 2016
"Hi Ben, Would it be possible to use the compost pit technique in an unheated greenhouse in the soil bed? Not sure if the temperature would be low enough or the bugs numerous enough! Thanks, Annie"
Annie Sutcliffe on Wednesday 23 November 2016
"Hi Annie.This could possibly work, though I'm not 100% certain. I think the main thing would be to keep the ground moist, so it doesn't dry out, which could slow or even stop the decomposition process. If you have nothing in the greenhouse you could leave the door open too. I'd say give it a go in a small area of the greenhouse to see how you get on. If it works, then you can extend it to other beds next year."
Ben Vanheems on Monday 28 November 2016
"Have been composting in trenches for my beans for years, and highly recommend it. For some reason I never thought of doing the same in holes for courgettes or tomatoes, will have to try for next years crop. Thank you!"
Carol Ann on Saturday 9 September 2017
"Good luck with it Carol Ann. I'm sure you're courgettes and tomatoes will thrive because of it!"
Ben Vanheems on Sunday 10 September 2017

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