By Pdb
Lancashire,
United Kingdom 
Potting on question.. Every year I ponder as to what size pot I need to pot on my seeds and every year I am unsure as to if the seeds are ready to pot on. I know its when the first true leaves appear but sometimes some are so small. I have attached a couple of piccys and wait to see what your advise is regarding these 2. First one is Verbascum Phoercieum , the second one is Campanula Pyramidalis. Thanks
17 May, 2012
Answers
Hi Bertiefox,Thanks for your reply. Are you saying then to leave the seedling in the pot as they are until roots show through? Would they not be too congested?
They are both annuals so I'm in no hurry for them to flower as I expect they wont until next year anyway.
17 May, 2012
You may be potting on your seedlings into too big a pot.
I would normally suggest potting on into a 7cm pot .
17 May, 2012
I doubt that they will be too congested if left for another week or even two. As the weather is still so cool, they are probably not growing too fast at the moment, which is why I think immediate potting on is not a good idea. Perhaps the best idea would be to carefully prick out the largest into pots, making room for the smaller to grow on. I often do this in stages.
17 May, 2012
Pdb annuals grow from seed, flower and die all in one year. The seedlings you are growing are perennials.
17 May, 2012
I prefer to sow seeds in the seed trays divided into cells, much less root disturbance, in fact if sown thinly there is no pricking out at all
17 May, 2012
Yes Moongrower sorry I meant perennials. I am going to have to get more trays that are divided into cells. I do have a few but I can see in the long run it easier.
17 May, 2012
I would leave them in the pot a bit longer but thin them out, pull out the weakest and this will give the other more space to grow.
17 May, 2012
Hello,
I sow small seeds on sowing soil in a tray. Each seed or each group of seeds is covered with a "small heap of dry sand". When plants are big enough, I use a tea spoon to transplant each plant together with some sowing soil and sand heap into a bigger tray.
You'll find more info and photos about this on my weblog:
Sjefgardentips.wordpress.com (29) Growing plants from tiny seeds.)
Sjef
16 Dec, 2012
Previous question
« My roses have yellow leaves with black spots. what do i do?
Potting on too early is far more likely to kill the plant than leaving it a bit longer. The key point is to leave them until there is a really good root system and there are roots beginning to protrude from the bottom of the pot.
Potting too early into a pot with a lot more compost means it is far too easy to waterlog the seedlings and the root system rots off.
Just check your seedlings are not too crowded and are ventilated well to avoid damping off or moulds forming.
Personally speaking, I am always in too much of a hurry to pot on, and I can speak with some experience about killing off tiny seedlings by drowning them!
17 May, 2012