Sand pit to garden

[Surrey.Winder]

We have recently moved into a new house and have removed a substantial above-ground swimming pool. What we have left is an area about 10ft by

20ft which is a depression of about 9 inches below the lawn. At the bottom of the depression is about another 9 inches of sand that originally served to give the pool a soft bedding. Effectively we have a rather flat golf sand bunker but not being a golfer we're keen to flatten it back to lawn or something more productive (e.g. a flower bed).

I could just get load of topsoil tipped into the depression and forget about the soil but not being any kind of soil expert I'm sort of nervous that having a large area of sand under the soil may not be a good idea. Not being an expert I'm also only really able to describe the current soil type as "normal".

Does anyone have any idea or experience of this sort of thing? Should I just bite the bullet and have it all dug up?

[David Hare-Scott]

I wouldn't leave the sand there and cover it up as it will not provide a good foundation for anything but the most shallow root systems. Probably the best solution is to bring in loam and amendments and till it all together. You would be aiming at heavier loams with some clay and adding organic matter and possibly some other amendments if the pH was way out or the soil was otherwise deficient.

You are aiming to end up with quality soil of good tilth that will drain at an acceptable rate. You don't want this area to become a pond in wet weather so you will need to investigate the drainage. You need to know during heavy rain where surface water comes from and where it goes to and what effect your earthworks will have on that. To take an example of a case to be avoided, if your basic soil doesn't drain well and the pool area is low and level then the sand pit will become completely waterlogged during extended rain, this is likely to kill your flowers.

David

[Billy]

What David is trying to ask is, is the adjacent soil clay? Sorry to butt in, it's all yours David\;O)

[Boron Elgar]

We did this about 10 years ago, but turned the bed into a flower and vegetable garden.

We got a load of cheap, but clean topsoil, then amended it ourselves with manure, compost, peat, mulched grass clippings and fall leaves, turning it all in frequently. It may help if you can rent a tiller for the early stages or enrichment to incorporate the sand into the add-ins.

What you have to add in may depend on the underlayment of the sand pit and the composition of the surrounding soil. You may be able to consult with your local extension service for advice, too.

It took a couple of years to get the soil to where were happy putting veggies and fruits into it, but today it is full of worms and is wonderfully friable and productive.

Boron

[Billy]

If the adjacent soil isn't solid clay, why not just have a back-hoe blend it a bit with the native soil, along with 5% organic material. If you could smooth out the depression of the trap, that may be all you need to do.

[brooklyn1]

Usually pool base sand is pretty fine, pointing sand, essentially beach sand. I would shovel it out and use it for building a patio, a base for a shed, something... pile in a corner until you decide, or sell it/give it away. For a decent garden you want decent topsoil, you would need to spend so much to amend sand (and it would still end up mostly sand because organics continue to decay) that it wouldn't be worth it. A spot where someone erected an above ground pool should be pretty accessible... ask the person who will dump the topsoil to first remove the sand (let him keep it), a small front loader should do that job in under a half hour... the sand should be payment enough. Contract for the price of the topsoil to fill the hole prior to mentioning the sand, if you get my drift.

[Surrey.Winder]

Thanks for all the feedback guys. I think that on balance I'm going to get the whole lot dug out and replaced with some decent topsoil!

[Billy]

Try to find out where the soil comes from. True, clean topsoil is hard to come by, and you don't want someone else's problem.

Even if it isn't topsoil, amendments and growing green manure, could have it presentable within a year.

[Ohioguy]

I wish I could trade you some of our heavy clay soil for some of your sand! Sandy soil is great for onions and many root crops.

[David Hare-Scott]

I have worked in both.

In one garden in sandstone country I had grey sand to start with and spent

20 years trying to build it up. You had to add much organic matter every year, fertiliser several times a year and in hot weather water it every day at least. Any excess water, which wasn't much, went straight through taking your fertiliser with it. Today it is more than grey sand but not a lot.

In another garden I have about 20-30 cm of clay silt on top of solid plastic clay. You spend your time building raised beds and planting trees in mounds not holes. There are some things I cannot grow due to lack of drainage. Now after 5 years of adding organic matter to break it down, in hot weather (hotter than #1) I have to water once a week and fertiliser once a year is enough. My beds are very productive. My pasture grows fresh grass 6 weeks after the last rain.

I'll take the clay thanks.

David