Forum home› Problem solving
This Forum will close on Wednesday 27 March, 2024. Please refer to the announcement on the Discussions page for further detail.

Seedlings in biodegradable pots

WildlifeloverWildlifelover Posts: 380
in Problem solving
Over the past couple of weeks, I have sowed annual seeds, indoors, in 8cm biodegradable pots. I’ve just checked some of them and roots are starting to pop out the bottom.

Does that mean they are ready to plant out? If so, frosts are still likely here during the next week. Will the seedlings be ok to be kept indoors with their roots growing out of the pots until the risk of frosts has passed?

 Thanks.

Posts

  • pitter-patterpitter-patter Posts: 2,429
    Are they hardly annuals? If not, it would be better if you waited another couple of weeks and then start hardening them off. 

    They should be alright with the roots growing out a bit, but what I do sometimes is put the biodegradable pot inside a plastic pot of similar size. 
  • tui34tui34 Posts: 3,493
    Absolutely!  Wait a while before planting out.  You didn't mention what kind of seeds they were - vegetable or flower.  Some are hardier than others but even so, they'll need hardening off before you even think about planting them outdoors.
    A good hoeing is worth two waterings.

  • WildlifeloverWildlifelover Posts: 380
    Thanks. They are annual flower seeds. The ones with the largest roots popping out are Cosmos seeds. 

    So, do I put the biodegradable pots into a larger plastic pot filled with potting mix, then harden them off for a couple of weeks, then plant out?

    Never done this before so apologies for the silly questions!
  • Nanny BeachNanny Beach Posts: 8,719
    Depends where you live I am in the SE UK, 10 minutes from the sea, and only sweet peas are out at the moment.i wouldn't bother potting them on,hah, yesterday I spent 3 hours potting on 3trays each containing 36 tiny plugs.We always do our hanging baskets at Easter,but it was early this year.They take such a huge amount of space and compost.Apart from the frost, slugs love these baby plants
  • pitter-patterpitter-patter Posts: 2,429
    Cosmos are quite tender. The reason I’ve said to put the biodegradable pot inside a plastic pot(without additional compost) was to protect the roots and keep the humidity in. This is just as a temporary measure to stop paper pots from drying too quickly.

    Depending on how large the plants are (cosmos grows fast) you can pinch the tip to promote side-shoots.

    If they get too big for the bio pots, you can repot into bigger plastic pots a bit deeper than before (part of the stem can be buried underneath the compost). I think cosmos can be tricky to grow in biodegradable pot as they grow fast, they tend to get leggy and they would benefit from planting deeper every time you repot them. I hope this makes sense.

    Some photos might help.
  • CrazybeeladyCrazybeelady Posts: 778
    I've got a few Cosmos seedlings and I had put a couple outside in a plastic greenhouse, just to see how they got on, and they were fine until earlier this week when I checked them and they looked like they were about to die.  Suffice to say they're back on my windowsill now and have perked up! 
  • WildlifeloverWildlifelover Posts: 380
    pitter-patter said:
    Cosmos are quite tender. The reason I’ve said to put the biodegradable pot inside a plastic pot(without additional compost) was to protect the roots and keep the humidity in. This is just as a temporary measure to stop paper pots from drying too quickly.

    Depending on how large the plants are (cosmos grows fast) you can pinch the tip to promote side-shoots.

    If they get too big for the bio pots, you can repot into bigger plastic pots a bit deeper than before (part of the stem can be buried underneath the compost). I think cosmos can be tricky to grow in biodegradable pot as they grow fast, they tend to get leggy and they would benefit from planting deeper every time you repot them. I hope this makes sense.

    Some photos might help.
    Many thanks.

    If I plant the whole bio pot with the Cosmos seedling into a larger plastic pot with compost would they be ok?
  • tui34tui34 Posts: 3,493
    @pitter-patter has given you some excellent advice.  Plant your bio pot into a larger plastic pot with compost, but don't put them outside yet.  Leave them where they are.
    A good hoeing is worth two waterings.

  • pitter-patterpitter-patter Posts: 2,429
    They will be fine, yes. Good luck and I hope they’ll give you lots of beautiful blooms later in the year.

    All my windowsills are crammed with seedlings and cuttings. I can hardly wait until I can get them all out. I’m even postponing pricking some of them out because of lack of space. I need a heated greenhouse!
  • Nanny BeachNanny Beach Posts: 8,719
    I've got ,3 green houses,full of bananas, citrus, agapanthus, begonias, pelargoniums,fuschias,brugmansia, agave,herbs,peas,beans,leeks, kitchen window conservatory window sills and large table full of seedlings seeds, pots
Sign In or Register to comment.