|Seed trays and containers on the patio, April 2017|
I try to raise most of my vegetables and annual flowers as transplants, to give them a better chance of surviving slug attacks. Some of these are tender and raised indoors first (tomatoes, cucumber, etc), but a lot can be sown in trays outdoors this month. I keep them high up, like on a table, to minimize slug attacks; like being directly in the ground, they're just as vulnerable in a tray if it's on the ground too.
For the most part I space the seeds at regular intervals in the trays, unless the seeds are too small to handle, like celery or snapdragons; these are broadcast, but I try to limit their numbers to around 20-30 seeds per tray. It's really easy to accidently tip out a hundred of these tiny seeds, and they're a real pain to prick out when all clustered together.
|Carrot seedlings in a container, April 2017|
As for the seedlings which I'm able to space regularly in the trays: brassicas, leeks, etc, I try to grow these on in their trays until they become fat little plants and transplant them into the ground. They're usually around 2 inches apart in their trays, giving them enough room to grow for about 6 weeks before needing more space anyway.
There's one vegetable I grow exclusively in containers, and that is carrots (I have the double whammy of slugs and carrot fly). These I broadcast and don't bother pricking out. I'll thin them out as they grow bigger, and eat the thinnings--or the seven year old will, or the husband will...they're very popular here.