
I have had a few folk saying them are having trouble germinating cleome seeds. This is understandable…cleome seed is not the easiest to germinate for your cut flower garden.
There is a great difference in opinion as to when to sow and at what temperature they desire before they will join the party. The one thing most folk agree on is that cleome seed requires fluctuating temperatures…lows of around 3 degrees and highs of about 20 degrees.
Previously I have made this happen by sowing early in the greenhouse…around about March…this way the trays will get the low temperatures no problem…the issue is they have to wait an awfully long time before they get the highs….(I know the feeling). This can mean that the seed rots away in the weeks they are sitting in the cold and damp.

This year I tried sowing some later…in April…(And also sowed a tray today as an experiment) …the ones I sowed in April have been reasonably successful….about 10 plants from a sprinkling of seeds on a module tray…but…well…it’s not amazing is it?
HOWEVER…having spoken to a selection of the best flower farmers from here to Auckland, and I have found another method…thus:
Sow in mid April..put the tray in a poly bag and put it in the fridge for two weeks….then back into the greenhouse….and all will be well…(it does not work to just put the seeds in fridge…they need to be damp and in the growing medium)
Now this is probably too much of a faff for most of us…so I conclude that you are better sowing late and accepting that the germination rates won’t be brilliant…but of course you can sow more thickly…and these can be big plants…having 20 plants would be LOADS.
…don’t be afraid my seed loving friends…feel the fear and sow it anyway.
Benjamin
Find Cleome seeds and more…in the Higgledy Seed Shop.
March 20, 2014 @ 9:54 pm
I have luck every year by surface sowing, and putting a plastic produce bag over the cell packs. All day sitting in the light, on a heating pad. Every night the cell packs go to a cool closet (not heated at all). Happy planting!
May 17, 2013 @ 8:58 am
I sowed a tray outside on 16 th April, I have no greenhouse :(. Also I live in sunny ( ehum, well it is today) Cornwall. they are just starting to poke through now. The last but one of my trays to show life. Looks like the natural Cornish climate worked its magic, if somewhat slowly, on these guys.
May 17, 2013 @ 12:46 pm
Cornwall is scorchio today…lots of rain for the rest of the country I hear…(ha ha ha!)
Glad your seeds have made an appearance. :)
May 12, 2013 @ 11:11 am
I sowed a tray on the 10th March this year and after a few weeks had no signs of germination. Then put the tray out for a couple of nights bringing back in during the day and placing next to a large french door – about half then germinated.
May 12, 2013 @ 11:25 am
ah haaaa! Yes…there we have the temperature fluctuations showing themselves…good work professor! :)