Viewing post #529625 by growitall

Leftwood said:... I'll put a quarter inch layer of almost pure regular potting mix at the bottom of the pot for two reasons: 1) to prevent the excessively sandy soil from falling through the holes... Depending on the seed, I use a surface grit layer of grit, on up to a cm deep.

I do most of my seed-starting in the little 2 1/2" square by 3 1/2" deep pots that alpines are often sold in; the bottom of these pots is open with only a little plastic cross across the center. Soil is kept from falling out by a little square of metal window screen or plastic mesh set in the bottom of the pot. I've started using a surface layer of grit (or sand) also - it seems to discourage the growth of algae* very effectively.

*Edit: Sorry, I should have said "moss", not "algae".

Leftwood said:...with more moisture retentive mixes I would sometimes get seed germinating at the edges of the pot, rather than all over the surface. This I attribute to the faster drying of the medium at the periphery.

Interesting... I often see that too with indoor growing and constant moisture. In my own case, I figure it's due to washing the seeds to the pot edges in the initial watering, as I often sprinkle the seeds directly on top of the soil mix, with no soil or only a little sprinkling of soil overtop.