What kind of sand is best for seed sowing?

[NaZzAtAzEr]

My current mix is 40% molar clay, 40% cat litter and 20% topsoil. This is too large for seeds so I want to put a fine layer of sand on top. I have some solver sand and it looks really fine. Is this ok or should I use coarse sand?

[Terry S.]

I think you need a finer moisture-retentive mix for seed sowing and I do not put any grit on top. The mix that I use is 1:1 John Innes Seed Compost and Meadow View Horticultural Potting Grit Eco which leads to very good root systems on the babies. The Grit is usually stocked by the independent garden centre on the east side of the A240 just south of Tolworth roundabout.

Incidentally the cat litter used by succulent growers is moler.

[Flayzerflay]

for top dressing i use molar clay that has been crushed and seived to 1mm, however lately i have been trying play sand applied to moist mix through a tea strainer, the sand soaks up the excess water and looks level, you can see the seeds and which ones germinate etc.

[daydreamer]

My current mix is 40% molar clay, 40% cat litter and 20% topsoil. This is too large for seeds so I want to put a fine layer of sand on top. I have some solver sand and it looks really fine. Is this ok or should I use coarse sand?

I use 2:1:1 coir (rehydrated from blocks), moler clay and the coarsest sand I can find. For seed raising I find the Europarts moler preferable to the Sanicat because it consists of smaller particles. I used to top dress with the same coarse sand, but didn’t find it offered any advantage over sowing straight onto the compost, provided it is gently tamped down to provide a surface without significant cavities. Small/fine seeds have a tendency to drop into these cavities and you end up with some seedlings that are too close together and consequently prone to damping off.

[Terry S.]

My philosophy in growing plants is to keep things as simple as possible. So using the 1:1 JI seed/Meadow View grit mentioned above, I sowed some Lithops seeds on the surface of the compost at the end of March. No additional heat other than what prevailed in the greenhouse, no plastic bags, and kept fairly moist by initially soaking from below and then regular mist spraying. Twelve weeks on, the results can be seen in the photos below; for an idea of scale the pots are 7cm across. Oh, and I didn't spend hundreds of bucks buying the seeds, they are off my own plants pollinated in Autumn 2018 and harvested late summer 2019.

[NaZzAtAzEr]

Thanks guys. I used sifted topsoil and small potting grit in equal (ish) quantities, bunged it in the microwave for 8 minutes then poured boiling water on it. Hope I get successful germination rates with my welcome pack seeds!