Unfortunately, it is all too common for gardeners to find their early spring compost to be a sodden, soggy mass of partially decomposed matter which looks to be unusable for months to come.
A soggy compost pile is usually caused by a combination of factors: poor aeration, too much moisture, and an imbalance between carbon-rich and nitrogen-rich materials.
The typical backyard composter does well at converting kitchen and yard waste into compost during summer and fall, when carbon-rich materials are readily available. But over winter, the new additions to the compost are mostly kitchen food wastes which are nitrogen-rich and have high moisture content. A healthy compost needs much more carbon matter than nitrogen, but carbon-rich materials are less available in winter. If the compost is not turned regularly, available carbon sources such as leaves and dried grass clippings can mat together, further reducing aeration and slowing the composting process.
A soggy compost can be restored in time for use in spring if you take a few simple measures in late winter/early spring. Here are some suggestions to remedy the situation:
1. Cover any open compost pile.
A compost pile should be moist but not soggy. Unless you live in a very dry climate, your compost pile should be covered, especially before the spring rains. If your compost is on the ground, drainage should be provided. A shallow trench can be dug to lead runoff away from the compost pile.
2. Add fine carbon material which will decompose quickly.
Adding carbon-rich materials will absorb some of the excess moisture in your compost and help restore the carbon/nitrogen balance needed for composting to occur. A simple rule of thumb is to use one-third nitrogen and two-thirds carbon materials. For a list of nitrogen and carbon materials commonly used for composting, click here. Bulky carbon materials, however, take longer to decompose. To revitalize a soggy compost for use in the next month or two, choose finer carbon-rich materials which will break down quickly. Here are some suggestions:
Lawn thatch – You can do a double service of aerating your lawn while improving your compost by using lawn thatch. Use a steel rake, or a thatching rake, to comb through your lawn and pull out excess thatch. Thatch is very fine and dry, and breaks down easily. It helps to absorb excess moisture in your composter, and “fluffs up” the composting materials. This promotes aeration which is critical to the composting process.
Clean sawdust – Very high in carbon, sawdust is a bulking agent that promotes aeration, and therefore, drying of compost materials. Be careful not to compost any sawdust or wood that has been “pressure treated” or otherwise treated with a chemical preservative. Likewise, avoid sawdust from chainsaws which use petroleum-based chain oil. Avoid cedar, cypress, redwood and juniper sawdust as they deter decomposition. Take care to sprinkle the sawdust in layers, or turn the compost while adding, so as not to discourage aeration.
Pine needles, forest duff – The fine bits of brown matter on the forest floor are carbon-rich and will help aerate the compost. Pine needles are acidic so we usually add lime when using pine needles. These materials are not as absorbent as sawdust.
Peat moss – While peat moss does not affect the C/N ratio, it is highly moisture absorbent and helps to balance the moisture level of compost.
Straw – Straw is not always available in the spring, but it is an excellent addition to the compost and very effective at promoting aeration. If you use straw, make sure it’s seed free. Stables and barns are a good source for bedding straw, which also have nitrogen worked in.
Last autumn’s leaves – If you saved leaves from last fall, they can be used to help restore a soggy compost pile. Shredded leaves work best. Care must be taken to turn the compost while adding leaves, or they will easily form mats which reduce aeration and slow the composting process down. Avoid using walnut leaves which contain a substance that inhibits the growth of many plants. Oak leaves take a very long time to break down because of their acidity and high levels of tannin. It is often a good idea to keep them separate to allow the main compost pile to finish sooner. Waxy leaves such as rhododendron, laurel, and lilac will take longer to break down and should be composted separately.
In our garden we store autumn leaves in the empty tomato cages, made using page wire. This is a good way of using the empty cages during winter, but we set the cages under the eaves of the garden shed to keep the leaves dry.
3. Turn or fork the compost
Now that you have added fine, dry carbon-rich materials to your compost, use a pitchfork or shovel to break up any large clumps of matted material. This is essential in any compost pile, since matting restricts aeration and slows down the composting process. If you have a tumbler–style composter this will be easy. Simply give the composter a spin each time you add materials. If you have a composter set on open ground this is more difficult. You can lift the composter off and let the composting material spill onto a tarp, where it is easy to mix in absorbent material. This can be shoveled into a wheelbarrow and applied to the garden beds, where it will continue to mellow.
4. Add a nitrogen activator
Finally, you can ‘reboot’ the composting process by adding a ‘hot’ source of readily available nitrogen. This is not essential, but will speed the process. If you have a stationery composter, take some finished compost from the bottom and add it to the top. If you don’t have finished compost, use garden topsoil. Other organic nitrogen activators include blood meal, manure, bonemeal, and alfalfa meal.
In early spring, gardeners are in a hurry to get finished compost. Moist and crumbly, finished compost spreads easily and can be used right away by newly planted starters. The above suggestions will speed the composting process, but if the compost is not quite ready when you need it, you can till the unfinished compost into the soil where it will finish off relatively quickly. And once you’ve been through the process of restoring a soggy compost pile, you’ll have a better understanding of how to maintain a compost pile through winter.