Attempting seeds for the second time - advice

[iann]

Thanks Ian, I left the thermometer in it overnight and it looks like it stayed at around 18 degrees, unfortunately I have no idea where the nearest Tesco is to me, would it work well enough without it?

You need something. Tesco cat litter is a really good thing that is available easily to most people. You might be able to find pumice. You can certainly find perlite, although I hate it. Horticultural grit, a nice fine grade like alpine grit for seedlings, is easy enough to find. There are other alternatives, I think Sophisticat Pink cat litter is the same.

[JamesEG]

I have to say I've never actually found pumice anywhere near me, and I have heard bad things about perlite so I'd rather not use it. I do have some horticultural grit but I think the pieces might be too large, it's about 5-8mm pieces. I was going to go to an aquatics shop tomorrow and see if they have any small grit, do you think that would be a good enough substitute?

[Aiko]

it's about 5-8mm pieces.

For sowing this might indeed be a bit too big.

You might also want to sieve rough (river or cement) sand you can buy at the garden centre of building store. There should be a lot of bigger particles in there, the size of about 1 or 2 mm. You might use those bigger parts to mix with a soil. You can use an ordinary kitchen sieve for this.

[iann]

Pumice isn't widely available in the UK. There are no domestic sources and little demand for it to be imported. Recently it has become available from specialist horticulturists, especially for bonsai, but usually expensive. Occasionally you may get lucky, or you can look online. Really though there is no need, with equally good (or better!) alternatives available all over the place. Research the cat litter, one of the appropriate brands will be available much more easily than pumice. Aquatics shops will have grits, but my experience has been that it is hard to find suitable ones. Just go to B&Q or any garden centre. Even a builders merchant if you are confident about identifying something that isn't full of limestone or salt. On a farm you might fond poultry grit, make sure it doesn't include limestone.

[JamesEG]

My Dad needed to buy food for our fish so I went with him and got some aquatic grit (2-3mm), I mixed it at around 60-70% with John Innes No. 2. The mix looks good so I'll see if it works well for the seeds, I sowed them today

[iann]

60-70% with John Innes No. 2

40% would be nearer the mark. Especially with just grit as the coarse material. Until you reach the point where the soil can't fill all the gaps between the grit, it is pretty much wasted. One check for this is whether the soil can be squashed. Enough grit and it is almost incompressible, maintaining air and allowing water to drain.

[JamesEG]

Thinking about it, it's probably nearer 50:50 as the soil does fill the gaps between the grit. So hopefully it should be okay