Filling in sinkholes with leaves and compost

I'd like to fill in the sinkholes in my wetland backyard with leaves and compost to enrich the soil. I've already filled them in with the leaves that just fell; now what? Do I buy soil, straw, sand, or potting soil? That sounds a bit pricey. I intend to compost using vegetable scraps from the kitchen. Would like to get the soil ready for planting trees ASAP, but realize it might take a year or so to build up the soil so it's rich and even with the rest of the yard. The sinkholes fill with water every time it rains a lot.
Thanks,
WG

The one thing to keep in mind if you're going to use leaves and things is that as they decompose they will shrink down in volume, so I'd suggest filling with soil instead, otherwise it may take forever to really level it out (or you'll end up planting your trees thinking it's level but it'll sink down again and they'll be sitting in water). You'll have to be careful with soil too--loose soil that you put in there will compact over time so I'd probably fill the hole so that it's slightly raised rather than just level, that way as the new soil compacts it'll end up level instead of another sinkhole.

If I were you WG, I would use the sink hole to my advantage ( I gather the sink hole is deliberately placed in certain low lying areas to act as a means of preventing rain water spreading all over the area) if so, I would not fill it in without adding heaps of gravel rubble etc to the bottom, once you have made to bottom safe and the size of the hole will take the amount of water you have sent down to you (on average) then you can start to modify the soil, this will depend on what type of plants / trees you want to grow, there are many, many, plants / trees that can only grow in the environment you can offer them by wet gardening or wet for lots of time in the year, the start of your choice has to be what type of soil is needed for your plants, like acid soil or natural soil etc, etc.
Next you have to look at wetland gardening, are there any in your area like parks, large public gardens or go to your local gov department who everyone speaks so highly off, as they would help keep you right.
I would also visit your local library and find books on wetland gardening, these will have ideas you can make on a smaller scale to suit your small spot, also they will have pictures of seasonal changes to give you ideas too. One of the dangers of planting trees that grow on wetland and planted close to drains, buildings etc as the roots will grow fast and cause damage to the mentioned property areas, this can happen un-noticed till you have a problem as the trouble is underground and you don't see it like you would with gutters etc so you need to be very careful what trees you use.
lastly, you don't have to have these wetland plants growing in deep water, most just like damp soil, shaded soil or damp for several weeks/ months, May i suggest that you spend the winter time looking at the shape of the wet garden, the plants you would like, their soil type and what grows well beside what, things like Ferns, Hosta's, lots of irises etc all like to be grown along the edge of wetlands, taller plants like Rogersia can take wetter conditions etc, so take the dark winter nights to plan out the shape, lay a hosepipe into a squiggle shape and go indoors to see it from the window to let you know where you need to reshape it, stick garden canes in the beds to represent plants / trees etc, this saves you making huge costly mistakes and then draw out the shape on paper with your planting ideas down the side, colour it in with crayons for summer, autumn and winter colours for when the leaves have gone. It is fun to make new areas of your garden and just enjoy the learning curve as it is cheaper than wasting mega bucks having to rip it all out because you have channeled the water somewhere else.
Good luck and have fun. Weenel.

Thank you, ecrane3 and WeeNel. You gave me a lot to think about. Now intend to spend this winter planning and take the ASAP out of it. I had planted a curly willow in one of the sinkholes and the wind blew it over because of the wet soil. Now I’m thinking of planting grasses suitable for wetlands and using the center for compost.

My husband puts dirt on some of the ares that water stagnates. If you are going to put grass than dirt first then compost. If you are going to put a garden I would put small rocks first for drainage then build it up with compost.

Belle

As with all trees newly planted, you need to stake them to give them support till they have put down enough roots to stablise themselves, I always look at young trees like my Kids, when learning to balance / take first step, you need to give them something to hold onto or they topple over, If you want to plant any type of willow, plant it on the very edge of the wetland garden as these plants have spreading roots that travel very far to take up the easiest water table, that includes drains at the house / land drains and within a few years they do cause considerable damage, The willow you have planted by the way is not the most invasive rooted ones and are grown more for the ornamental twisted branches that on mine give beautiful catkins in spring before the foliage arrives, this plant is worth replanting if you have not already thrown it out. good luck. WeeNel.

I agree with WeeNel et al. You really need to layer in some gravel or loose rock/shale for a base and drainage before you begin to fill with dirt, leaves, compost etc. Remember too that if the sinkhole continues to hold water even after it is filled in, the soil may become "sour" with rotted leaves and compost. You'll need to keep an eye on it so that it doesn't cause decayed roots in anything you plant there.

A good way to keep wet / damp soil from going sour and keep it sweet is to add a few bags of Charcoal to the bottom of the hole, the stuff you use for the BQ, this helps prevent that smell stagnant water can have but not always and it is charcoal made from wood so it is not adding any chemicals to the soil either. Good luck. WeeNel.

I'd bet Wetlandgardner has nothing more than a low spot due to a long gone tree whose stump and below surface root system has gradually rotted away, leaving a slight depression. This is quite common in older home landscapes like Anchorage KY - which I'm very familiar with.

The best answer (if a depression in the yard is unsatisfactory) is to level it up with normal soil that matches the surrounding soils. There really isn't any need to create "drainage" with rocks or anything else, since the surrounding soils are identical. The only reason water gathers there at all is because it is slightly lower. When leveled, water will be spread evenly across the surface and infiltrate at similar rates.

If you like a low spot to gather water preferentially, that's great - plant things that appreciate the directed moisture. This site isn't likely to support wetland species, however, since this part of Kentucky has limestone strata and the soils are pretty well drained. Anchorage is situated on a high point, even - and several significant stream systems begin there.