The big squeeze
When it comes to sowing seeds and pricking out seedlings, space is always at a premium, says Bob
IWAS asked the other day why it’s always recommended to sow, prick out and then pot on, and why we don’t just sow in the pots they’re going to grow in straight away. Which, of course, you can do for some. As always, it’s horses for courses. The main reason is obvious: you can squeeze more in.
Space in a warm propagator, coldframe or even on the greenhouse bench is always limited. By starting off batches of seedlings in small pots and then pricking these out into trays or cells, you fit more in. Furthermore, as each batch of seedlings grow, you only pot on the best (more if you can’t be ruthless enough), thus ensuring that most become fine specimens. But there is a cost to this: each time you move on a seedling or plant, it receives a check to growth – and the more so the older it has become. This is mitigated by the roots now having more compost to grow into, but nonetheless it does set plants back temporarily.
Moving sooner is better than later, as not separating seedlings early enough can be even more disastrous but go unnoticed at the time (a sin of which I suspect we’ve all been guilty). Once they have started to develop beyond their seed leaves, seedlings are competing with each other in a way that is worse than weeds. Even when potted up, growing plants will soon fill their new cells or pots (exhausting their compost), and you risk them stopping growing unless you feed or pot them up once again. Thus, the skill is in keeping each batch moving on into larger containers as fast as all the plants expand.
And you must do so before you run out of space for all of them. Of course, this may happen, year after year, despite your very best intentions – but then that’s gardening for you!
“The skill is in keeping each batch moving on”