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skipduke

sunflowers

skipduke
10 years ago

I planted 15 sunflowers on the 17th of feb and only 3 have sprouted so far-they have their first true leaves growing at this rate. The other 12 seeds I planted haven't appeared.
Curious to know why this is.
On the 11th of march I planed loads morse sunflowers and they are all sprouting now.

My sunflowers are in a ingested greenhouse and receive full sunlight all day.

Comments (11)

  • samhain10 - 5a
    10 years ago

    They should have sprouted way before now. Sounds like you may have gotten a bad batch of seed? If you have any seed left, you might try pre-germinating it folded in dampened paper toweling that you slip into a polybag - the thin kind you put fruit and veggies in at the grocery. And my latest thing is to take fingernail clippers and nip the edge of the seed coat of hard seeds to aid moisture getting into the embryo. If you don't see something germinate from that, then you definitely have bad seed. Don't know about over there in Ireland, but here I've often run into the problem of sunflower seeds having been hit by bugs, even some of the stuff I've bought at stores - basically an empty seed case with no embryo!The eggs are laid in the seeds before they're even harvested, and the larvae leave a little hole where they exit after eating the embryo.

  • floral_uk z.8/9 SW UK
    10 years ago

    The compost looks rather wet - they may well have rotted. Also is there any heat in the greenhouse? I'm assuming 'ingested' is predictive text trying to say 'unheated'?? It was probably still too cold for sunflowers when you sowed them and cold + damp = rot.

  • skipduke
    Original Author
    10 years ago

    Yes sorry ingested was a typo. I meant unheated. Still though, the greenhouse reaches around 20degrees Celsius (on a cold day) and doesn't go below freezing point at night time. I watered all these plants the same amount every few days, also there's vermiculite included in the soil so I dont think waterloggoing would be a problem. I also planted 20 seeds in a window box, 9/20 have germinated which is significantly a higher ratio, but still unsatisfactory. The posit I added here is from the sunflowers planted on the 11th of May

  • docmom_gw
    10 years ago

    I agree with Floral. The cold night time temps slowed germination just enough to allow rot. A few weeks warmer, and germination is much better. I bet the seeds in the window were slightly warmer, so had slightly better germination, but still not as good as the much later seeds.

    Martha

  • mandolls
    10 years ago

    I have not grown sun flowers, but have some seed for this year. Everywhere I read it says to direct seed them. Does any one have good experience with getting them started inside first? I start almost everything else under lights, and would like to get mine going if they will do well.

  • floral_uk z.8/9 SW UK
    10 years ago

    ' I watered all these plants the same amount every few days'. If you watered the February sowing at the same interval and quantity as the March sowing, and the February sowing was not growing due to cooler temps, then they were getting too much water. The green algal growth on the surface of the compost also indicates that it is too damp. Perlite can't prevent waterlogging if there is too much water going in. The March sowing would have been that bit warmer enabling them to germinate before they rotted. If you dig around in some of the empty-looking pots I imagine you will find either no seed or a rotted seed.

    This post was edited by floral_uk on Sat, Mar 29, 14 at 11:04

  • SouthCountryGuy Zone 4b-5 SE BC
    10 years ago

    mandolls, IME and as you have read sunflowers started in pots don't do as well as those directed seeded. The tap root grows very, very fast and unless you have a huge pot it will be out of the bottom in days. Last year I had 150 sunflowers in 60 varieties and every plant I started indoors was considerably smaller than ones direct sowed. As an example the 'Russian Giants' I started indoors grew to ~10' and those direct sowed beside them grew to ~14'. It was less noticeable in smaller varieties but the other interesting thing I noticed was that the ones started inside didn't flower any faster either. IMHO it just isn't worth starting them inside for any reason other than boredom.

    Have a great day.

    SCG

  • docmom_gw
    10 years ago

    Also, if you are trying to grow them under lights, you run out of head room in no time.

    Martha

  • mandolls
    10 years ago

    Thanks SCG - my indoor lighting space is getting really full, so I'll hold off on them and direct seed.

  • SouthCountryGuy Zone 4b-5 SE BC
    10 years ago

    +1 docmom I forgot about them growing 3" in less than 12hrs and scorching themselves on my lights.

    SCG

  • samhain10 - 5a
    10 years ago

    SouthCountryGuy - you know, you're absolutely right on all counts - thank you for reminding me! I made a Sunflower House last year and posted about it in the Gardening with Kids forum. By misadventure, I lost most of the seeds I started in pots and had to direct plant in mid-May, worried that I might not see bloom on everything before frost. I was totally wrong! Not only did everything bloom, but all matured to set seed for the chickadees and other birds to feast on in the fall. I'm planning on making another Sunflower House this year since I enjoyed it so much. :)