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Seed Advice for a Complete Novice :)

Hi, I have purchased a few packets of seeds, some perennials (Lychnis Coronaria/Delphiniums/Thalictrum) and some annuals (Ammi Majus).

I am just a bit confused about the whole process and was hoping for some rough guidelines.

I have potting compost, potting grit, seed trays with see through plastic covers, a south facing window in my kitchen, a shed with a window and one of those plastic mini greenhouses.

I generally prefer to sow in seed trays where possible and I try to follow the instructions on the packets, like which ones require heat/light.

So... my general process will be:
  1. Fill seed tray (Modular Seed Tray for bigger seeds) with leveled potting compost
  2. Sow seed and then water from below
  3. Cover with thin layer of grit unless instructions state require light to germinate
  4. Put on plastic lid and leave on kitchen window sill. Keep moist with water spray.
  5. Wait until seed germinates and then remove plastic lid
  6. Wait until first pair of "true" leaves emerges then prick out if in seed tray
  7. At this point should I move the seedlings to my mini greenhouse/shed to grow on or will it be too cold?
  8. Then when big enough after a few weeks, start to harden off by moving outside gradually for up to a week

Does that sound roughly the right idea?

I think my main confusion arises around when to take the plastic lid off and when/where to move from my kitchen to the mini greenhouse/shed. Unless I can leave all my ungerminated seed trays in the mini greenhouse from start to finish? Or is a coldframe better for this job?



  • PurplerainPurplerain Posts: 1,052
    edited March 2019
    You are doing everything right, but I would hold back on the perennials until July/August and overwinter where possible.

    I leave the plastic lids on until they germinate then open the vents for around a week. Keep turning them around to the light. Don't overwater but don't let them dry out. After that I remove the lids completely and keep protected indoors. Once the second set of leaves appear, pot them on into either big cell trays or small pots. By then you should be able to put them outside in your greenhouse or cold frame.
    SW Scotland
  • Carlos99Carlos99 Posts: 4
    That's great, thanks for your advice. Sounds like I'm not too far off the mark. Is the optimal setup for seeds a grown up greenhouse with a heated mat? 
  • LynLyn DevonPosts: 18,005
    I’ve never sown any seeds on a mat or propagator,  if you sow now on your window sill they’ll be just fine, when they’re big enough to be pricked out and potted up, the weather and light levels will be even better. 

    With the exception of the Thalictrum which I’ve never grown, there nothing there that need heat.   Think of nature, those plants drop their seeds, next Spring they grow, no one goes out with heaters for them.  When the times right they pop up. 

    Seeds grown indoors do need to be hardened off gradually,  I use the plastic GH with the zips open, just close at night for a week or two then leave open. 
    Gardening on the wild, windy west side of Dartmoor. 

  • Pete.8Pete.8 Billericay, EssexPosts: 7,246
    I collected seed from my Thalictrum, sowed in a tray of gritty compost in October, left in a sheltered spot behind my greenhouse over winter and about 5 seedlings have recently appeared amongst the weeds. I sowed eryngium in Summer last year too and they're starting to appear as well.

    If you're sowing seed that requires light to germinate, you can cover them with a sprinkling of vermiculite which lets light through but keeps the seed just right for germination.
    I never sit my seed trays in water once sown as I find it gets waterlogged. If it's big seed (e.g. dahlias) I just use a watering can with a fine rose. If it's small seed and vermiculite (e.g. petunias) I use a hand sprayer with water  - just check daily to ensure they don't dry out.
    Knowledge is knowing that a tomato is a fruit.
    Wisdom is not putting it in a fruit salad.
  • The other thing that I do when the seedlings start to emerge and get bigger. I get some old flat cardboard and put foil around it. I then place it behind the pots, this reflects the light and helps them to grow straight, without too much worry of turning them around every time. Especially if you have grown a lot.

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