Ahoy there! Let us have a quick delve into the world of the half-hardy annual flower.
What is a half-hardy flower?
Half-hardy annuals such as Cosmos, Rudbeckia, Zinna and Nicotiana will die if exposed to the cold, so they can’t go into the garden until after the last frost. Generally, these flowers will be native to somewhere more toasty than the UK where they can lounge about at their leisure setting seed more or less when they like due to the lack of seasons and the lack of cell-damaging frost. Here in the UK, we are big into seasons and any visiting plants have to tow the party line. This means we have to do one of two things. Either, sow them in pots under glass, or sow them directly into the soil after the frosts have wobbled off. The lines can be blurred as to which plants are hardy and half-hardy, it’s not an exact science. The Higgledy portfolio of seeds leans more towards hardy flowers but we have plenty of half-hardy ones too.
How do we grow half-hardy flowers from seed?
Sowing directly into the soil:
Many flower farmers I know sow their half-hardy seeds straight into the soil. Most wait until May before doing this, when the soil has warmed up and frosts are unlikely…at least they are unlikely to happen after the seedlings emerge. We had a fierce frost on May 17th a few years back that wiped out a few dozen Comsos that I had started under glass in April and planted out on May 1st. I was most miffed.
Half-hardy flower seeds tend to be very fine or slight….don’t sow them very deep….better still, just cover them with a light cover of compost. Sowing in straight drills will make it easy to see what is a seedling and what is a ‘weedling’.
Sowing in pots:
Sowing in pots is the preferred Higgledy method. To the uninitiated, it may sound like more work but it is often considerably much less so. ‘How so?!’, I hear you cry. Well….once you have sown your seed directly into the soil, the native weed seeds will also join in the fun. Native weeds are more adapted to our soils and climate and will outcompete our chums the half-hardy seedlings. A chap can find himself spending hours weeding around tiny seedlings and once again feeling most miffed. If you have sown in pots…from say early April, your seedlings will be biggish and strong and ready for adventures in the outside world by mid-May. At this time you can gently hoe off any weeds on your flower bed and this will massively slow down any further weed growth. Simply plant your seedlings about a foot apart and mulch around them with some compost if you have some spare…this will annoy the weeds further.
I wouldn’t start sowing before the spring equinox, which is around the 22nd March. Most of my half-hardy annuals get sown in early April.
I use 3-inch square pots…15 sit nicely in a standard seed tray and the pesky slugs find it difficult to hide anywhere between the pots. Use good quality compost. I use Melcourt compost. 15 seedlings will fill a meter and a half….so a large tray holding 4 seed trays will cover 6 square meters. It’s important to be aware of this. Lots of folk tend to grow several times more seedlings than they need in very small pots….this usually results in weak and leggy plants…do not make this mistake….you will look foolish and it will be your turn to feel most miffed.
Which half-hardy flowers will be grown in the Higgledy Garden this year?
I will have to ask Higgledy Anne and Higgledy Gemma what they are growing in their cutting patches…and I’ll ask them to let us all know. As for Flash and me…we will certainly be growing our ‘fav five’, Rudbeckia ‘Irish Eyes’, Zinnia ‘Cactus’, Nicotiana ‘Lime Green’, and Cosmos ‘Purity’. We’ll also certainly grow climbing Rudbeckia ‘Flash Mix’. …and I think Anne might have started me a few Cobaea, because she is lovely like that.
All of these can of course be found in the Higgledy Garden Seed Shop.
Your Half Hardy Annuals should flower from July, right through until the November frosts.
I hope this has been useful and has set you on a path to cut flower patch stardom. ;)
Higgers and Flash
In unrelated news….it’s snowing in Boatland!