Loosen clayey soil with sand

Since we want to start with our garden, I received an important tip yesterday.

Our property is on a former forested area. The soil is very clayey and stony.

Yesterday, a landscape gardener said that the top layers must be loosened with sand, otherwise the water would stand in the garden after every rain.

Currently, we need to fill in about 30 cm of topsoil anyway.
To me, it sounds plausible, but out of 3 companies that were here, he was the only one with that tip.

Is that justified, or does he just want to make money?

Basically, water seeps very slowly or almost not at all into soils with a lot of clay and loam. That is correct so far.

The topsoil that is to be filled in will probably have a different quality and will initially absorb rainwater. And depending on the amount of rain, the soil will eventually become saturated. However, this is the case with every soil, just some earlier, others later.

Is there anything against waiting 6 months and observing the rainwater runoff behavior?

There may be some reasons against it. If in six months you can no longer get into the garden with heavy equipment or the fact that the garden was just laid out and then dug up again.

We also have very clay-rich soil. Most homeowners were smart and took care of "infiltration holes" and drainage when laying out the garden. Some are only trying now – the garden is finished, no larger excavator will come in anymore – to get the standing water under control. First, that is difficult and second, it’s annoying when holes are dug directly into the fresh lawn again (gravel is then put in there) or drainage is installed.

We decided yesterday to fill approximately 20-30 cm with recycling material, install a drainage in this area, and then put the topsoil on it.

I think this is a cost-effective and good solution.

We had clayey soil in our garden in our rental apartment and not much grew there and there was also the water problem. Topsoil or sand help well in such cases.

Sand is the best solution. When installing the recycling material, you should be careful not to compact it too much. We have created an infiltration option in addition to the sand installation.