How and when to sow annual flower seeds
Now that you have a list of plants to grow in your cutting patch, it’s time to start thinking about sowing some seeds. Exactly when to start sowing depends on a number of things – the weather, soil conditions, and how much space you have indoors to grow plants before they go outside. April is usually a good time to start seeds in the UK. The light levels are good and the soil is warming up.
You can sow sweet pea seeds directly into the ground later in spring but, if you have space, starting them now will give you stronger plants and earlier flowers. Sweet peas have a tough coating to the seed. Some people recommend making a small nick in the seed coat or soaking them overnight in water to help speed up germination. This year I’ve been using a trick I learned from Twitter, and have put the seeds on a piece of kitchen paper soaked in water, then folded it over to cover the seeds. I’ve found this a really useful way to see which seeds are going to germinate. As soon as the seeds show any signs of growth, I very gently move them to a pot of compost. Sweet pea plants have long roots, so find the deepest pots you can, or invest in some root trainers that are specially designed for sweet peas. It is also possible to use the cardboard tubes from the inside of loo rolls. Stand them upright in a container (one with drainage holes in the base), fill them with compost and water well. Make a hole in the compost – about 2cm deep, and gently drop a single seed in. Cover with compost and leave in a warm, mouse-free place. Mice love sweet pea seeds, so make sure they can’t get at yours.
Half hardy annuals
Cosmos, rudbeckia, snapdragons and zinnias all make fantastic cut flowers. These plants can be sown indoors in March or April and grown on protected from frosts before you plant them out into the cutting garden in late May or early June. Fill a small pot with some finely crumbled, peat free multipurpose compost. The right texture is key – seeds like a fine soil so that the delicate new roots don’t come up against big lumps that they can’t grow through. Gently firm the top of the compost to level it and make sure there are no big air pockets. Water, again gently, to ensure the compost is damp right through but not soggy. Sow the seeds following the instructions on the packet, label the pot and put in a warm spot to germinate. If you have a propagator, put the pot in it to help maintain a nice humid environment. Depending on the temperature and the type of flower, you may see signs of growth in a few days or a couple of weeks.
Hardy annuals are great if you have limited space for starting seeds indoors. They can be sown directly into the garden once the soil has warmed up in late spring. One word of warning – don’t try sowing them too soon. Depending on the weather and where in the country you are, early April is the soonest you should be even thinking of sowing directly. The general rule is to wait until the weed seeds start to grow – a sure sign that the soil is warm enough to start seeds.
Prepare the soil by removing any weeds that have already germinated, and raking it or using a hand fork to create a fine texture. Make shallow lines or zig zags in the soil, water if dry, and sow the seeds thinly into these. Sowing in straight lines makes it easier to spot which seedlings are meant to be there and which are weeds as the young plants grow. Cover the seeds with a little soil. You might need to protect the freshly sown area from the attention of cats or birds if they are likely to scratch up your seeds. This is easily done by laying some fine netting or thorny twigs over the soil.