Kitchen Garden Forum

Found a tip on a website which recommended mincing up old sponges or chopping them into tiny bits and mixing them in with compost in hanging baskets and patio containers to help retain moisture, and save the cost of water retention gels. Might give it a try as we have light gravelly soil which dries out very quickly in summer and the water retention crystals are quite expensive to buy, especially if you need to treat a whole vegetable patch.

Dear Primrose,
What a good idea. The simplest ones are the best, they say.
Regards Gerry.

The sponge might hold water but personaly I'm reluctant to mix anything that won't rot into soil or compost.

Having used polystyrene packaging as drainage in several pots I then had to try and pick crumbs of the stuff out before putting the exhausted compost into the compost heap. Not suprisingly some evaded me, and several years later I'm still coming across them on my plot.

I wonder if cellulose based cat litter in the bottom of hanging baskets would be as effective as a water store. It says on the bag it is compostable.

Hi Di,
If you use a Natural Sponge then it will ultimately compost. Natural products such as Vermiculite and Perlite will not compost but will do no harm whatsoever but will also increase the water holding properties of a compost.
Man-made products such as Polystyrene should not be used generally but do no harm to plant life however annoying they may be visually.
JB.

Hi JB,
I sort of assumed we were talking synthetic sponges, as natural sponges are generally small and expensive.

While I take your point that other additives don't rot, but aren't damaging, I still prefer to avoid adding such if there is an alternative.

I'm not a mad puritan, but I'm increasingly alarmed at how people dispose of topsoil as if it were rubbish. I try to make sure it, and all my compost etc, stays were it is -over the years the build up might be significant.

It's not exactly natural material, but another good one is to break up Oasis (the green flower arranging foam) to add to compost instead of water reating gel.

Sue

Sue - that's another good idea. Think I'll have to be nice to my local florist and enquire whether they have any reject Oasis they would normally throw away.

Dear Sue,
whatever oasis is made of it comes out of our compost heaps in exactly the same state it went in and our heaps sit for three years....
Regards Sally Wright.

Hi Sally.

Point taken, but I get round this by using an old kitchen knife to cut big chunks or slices of Oasis and then I put a few bits in the bottom third of my containers. It does as good a job as expensive water gel and is easy to pick out when you are done.

I have been known to dry it out and re-use it - stingy old watsit that I am Would not suggest this if you have had disease problems with the plants in question mind.

Sue