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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Show 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
"I want to follow no dig principles. Doesn't digging a pit or trench defeat those principles. I use bokashi in my compost and would like to dig a trench to plant it in like your suggestions but afraid this defeats the no dig principles and kills off the microbes like tilling. What are your thoughts in this? Is there another way like lay on top and cover with a compost? "
Alan Shrimpton on Wednesday 21 February 2018
"Hi Alan. Yes, sprinkle bokashi over the soil surface and cover with compost. Digging pits or trenches is a great way to compost in situ. It's not strictly compatible with no-dig, but then I wouldn't be a slave to no-dig - just no-dig generally and if you need to dig to make compost trenches, dig out potatoes etc. then so be it."
Ben Vanheems on Thursday 22 February 2018
"I live in Ojai, CA. Are citrus peelings acceptable for composting this way? "
Renita on Sunday 25 March 2018
"Absolutely, but add it in small amounts with plenty of other material."
Ben Vanheems on Sunday 25 March 2018
"From spring through fall, my mother-in-law, who had the most amazing garden soil, used to puree vegetable scraps in her blender to make a thick "soup" and then bury it in her garden beds. I think this is good way to deal with scraps when the compost pit can't take anymore, but I wonder if there is a problem with this method. Thanks"
Marti Edmondson on Saturday 21 April 2018
"The only thing might be that pureed scraps could potentially attract vermin, but if they're properly buried then this shouldn't be too much of an issue and the material should rot down quicker. If your mother-in-law had amazing garden soil, then clearly she was onto something good!"
Ben Vanheems on Monday 23 April 2018
"hi really enjoy reading comments here, was wondering ,have been told ,blight can only live through winter ,if green matter left in soil, does kitchen scraps feed them when dug in winter? tu seem to have blight ever year here in ga tu so much"
bobby bennett on Saturday 5 May 2018
"Hi Bobby. Blight doesn’t usually survive the winter, so you should be fine. That said, I would avoid composting/burying heavily infected material, just in case. Fresh material from the tomato/potato family, if added to blighted material, could potentially prolong the life of the disease too, so would be best avoided."
Ben Vanheems on Sunday 6 May 2018
"Could you direct me to an article containing extensive details regarding food items that should and should NOT be added to compost? I'm wondering about leftover pasta, perhaps chicken, watermelon chunks that have fermented in the fridge...egg shells, etc. Thanks!"
Ryanne on Wednesday 23 May 2018
"Hi Ryanne. What you can compost really depends on what sort of composting set up you have. If you have a really hot composting setup (search 'hot composting' in the search field at the top of this webpage) then you can probably get away with things like bread and leftover pasta, in small amounts. Better still is to perhaps install a countertop bokashi bin (search 'bokashi' in the search field at the top of this webpage), which acts as a sort of pre-composting stage for all kitchen waste, including cooked food."
Ben Vanheems on Thursday 24 May 2018
"can you put some more videos about composting "
Ashlynn on Thursday 13 December 2018
"Hi Ashlynn. We have lots of articles and a few videos on composting. To find them, simply search 'compost' in the search box at the very top of this webpage. Enjoy!"
Ben Vanheems on Thursday 13 December 2018
"Really useful video and instructions thanks. Are in situ compost pits worthwhile to do for flowering beds? even if you not planning on growing vegetable crops?? Thank you "
Rosalind Wareing on Friday 5 April 2019
"They could be worth doing for flower beds, but to be honest this would be quite a labour-intensive way of preparing beds if it's for quite a big area. But it would certainly work and would be welcomed by the plants. Composting pits are generally reserved for hungry feeders like squash and beans. But you could try them under large, leafy perennials to get them going quickly and strongly."
Ben Vanheems on Monday 8 April 2019
"What is the statement of the problem? Just asking.. :)"
Sci_Girl on Friday 12 July 2019
"Sci_Girl I read it, the question is simply, "Are in situ compost pits worthwhile to do for flowering beds?""
Ryanne on Sunday 14 July 2019
"Yes, compost pits can be made for flower beds. But it takes a lot of effort, so best reserved for one-off pits for hungry feeders like beans and squash."
Ben Vanheems on Monday 15 July 2019
"Compost in situ, can it used for a perennial flower garden?"
Kathleen Chandler on Monday 8 February 2021
"Yes, absolutely. It would be ideal for any hungry perennials that typically put on a lot of growth in a shortish time."
Ben Vanheems on Tuesday 9 February 2021
"Thank you Benedict. You don't mention invasive weeds (couch grass, mares' tails, wild garlic etc. etc. ). Don't you have to get rid of these before you make any sort of compost? Ys, Annie"
Annie on Saturday 10 April 2021
"I wouldn't put invasive weeds (certainly the roots) in a compost trench, as the roots may survive and then start growing. These weeds can be buried at the centre of a full-sized compost heap where they should give up. Or you can simply submerge them in a bucket/tub of water, with a lid on to exclude light, and wait for them to drown. It sounds macabre, but it works - and then you can put the resulting slop onto the compost heap/into compost trenches. "
Ben Vanheems on Tuesday 13 April 2021
"Thanks for your article. I have been using the in situ method for many years. Every day, I dig a hole in the garden and dump in the days peels, seeds and other veggie parts. Cover it up and it's gone in a couple of weeks... I don't like to add the white egg shells because they seem to reappear. Thanks for the tip on drowning the weeds.. I'll try that!"
Sara on Wednesday 8 December 2021
"Hi Ben! After watching your video on composting in situ, I have gone one step farther which makes using all my kitchen scraps a much easier process. I save all scraps, including coffee grounds, tea bags, egg shells, etc in a bowl all day - then I put them all in my food processor and voila! I have instant compost that looks like rich soil. I even added a paper towel to see if it would go - and it too ground up perfectly. Ready to spread on top of the soil. It is AWESOME!!!"
Ann Capozza on Monday 3 January 2022

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