Compost Water Retention

[LexLucre]

Do people find the water retention properties of multi purpose compost varies a lot?

I live in London so my choice of convenient compost sources is rather limited, so I often buy whatever is cheapest at my local b&q, often the 120l bags of own brand.

This time the only thing they had left was peat free, and knowing that I should probably be switching to this anyway I bought some. I'm noticing after watering that almost all the water comes out the bottom, and the soil is completely dry at the top much more quickly. Most of the compost I buy behaves differently than this - water would only come out from the bottom if I really saturated it.

Is this desirable, poor quality, or is that dependent on what I'm growing? I know a lot of things talk about free draining compost, and I know sand and grit is sometimes added under the guise of improving drainage, but this stuff drains instantly.

I thought it was maybe the peat that made compost more absorbing, but a bit of googling put doubt on that.

I've just realised how dull this post is, sorry...

[sparrow100]

If you haven't put yourself to sleep yet...peat-free compost needs slightly different watering, and different brands can take it to extremes.

I use SylvaGrow as seed and potting compost, which is pretty good on water retention, though not as much as peat. I have a heavy watering hand (drought might train me out of that) so it works for me. If I need it to be a bit heavier I mix in some home made compost and a spade's worth of crumbled soil. That makes it much more water retentive cos I'm in London too and my plot has lovely clay...

Back to snoozing. Zzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzz

[sparrow100]

PS I hate their peat-free offerings. New Horizons isn't bad, SylvaGrow is better and Westland/GroSure is ruddy awful - in my experience.

[vixylix]

I have normal B&Q standard stuff and I'm finding that it drains terribly fast too - I havent had problems before. I put it down to it just being really warm weather before stuff has really settled its roots in?

[Cadalot]

I mix coir with B&Q verve, it works for me.

[Kirk]

Not sure if available to you but I have just bought 5 bags of peat free, the 20 litre ones, from Lidl, 99p each. About 30 minutes ago. Actually quite impressed by the stuff. What came out of the bags was a lot better then I expected.

Usually peat free means semi composted twigs and shreddings but this stuff appears surprisingly good. Also from the smell of the stuff I would take a guess that it has a degree of manure in it.

At 20 litre it is easy to carry as well.

[Snadger]

You could use the water retension granules mixed in compost?

[hop-a-long]

I've also given the lidl 99p peat free bags a go, and find them pretty good too! It seems to hydrate pretty well, and holds its structure after watering pretty nicely too. I'm mixing in a bit of chicken manure pellets when I'm potting on just incase it's really low on nutrients. Maybe a bit of John innes no 3 would be a good addition to the mix... Or would that defeat the purpose of going peat free?

[Snadger]

I've also given the lidl 99p peat free bags a go, and find them pretty good too! It seems to hydrate pretty well, and holds its structure after watering pretty nicely too. I'm mixing in a bit of chicken manure pellets when I'm potting on just incase it's really low on nutrients. Maybe a bit of John innes no 3 would be a good addition to the mix... Or would that defeat the purpose of going peat free?

As JI 3 is just sand loam and peat, you could just add sand and loam to existing compost to create a JI 3 type mix.

[Snoop Puss]

Interesting to hear the comments on the Lidl stuff. Mr Snoop bought me a bag here in Spain. My expectations were low, but it is fact very good. Much better than some of the more expensive so-called 'professional' stuff I've bought here. That said, the Lidl compost I've had in the past hasn't been up to much, so maybe this is just a good year.

Don't much like the coir-based stuff for the same reason, but I've taken to giving it a good soaking from the bottom for quite a while before sowing in it. That seems to help. But even then it's not great despite the fact that it seems to have added sand.

[rary]

When I have problems with water retention in compost I usually mix in some soil to help hold water, I know not everyone has access to soil so try mixing in some washing up liquid to your compost, in the past when peat based composites dried out and the water just run through , it helped if you added liquid soap to the compost, it helped break down a waxy skin on the peat, whither it will work on peat free I don't know but worth a try