When should I start my seeds? This is a question I see on various garden groups all over the lower mainland of BC. First let’s examine what you are trying to grow. Are you growing vegetables or flowers, annuals or perennials? Once you’ve answered this question it gets easy. The whole idea that plants are all planted in May doesn’t work for many plants.
For the most part annual vegetables take about 6-8 weeks from seed to the transplant stage. It’s best to know your last frost date and count backwards 6-8 weeks and plant your seeds inside. If you start too early your plants will be large and harder to transplant. Here in the Vancouver area our last frost date is the end of March. That means the soil will start to warm up in March and cool season crops can be planted. Cool season crops are spinach, kale, lettuce, radishes, potatoes, peas, Pac Choi, mustard greens and chervil. As you can see they are mostly salad greens and they are easily direct sown right into the garden. These crops like soil temperatures over 5C so get yourself a soil thermometer and check your soil before planting. Cold soil leads to rotting seeds and lack of germination. Since we can plant cool season vegetables in March and April seeds can be started in late February inside if you want to plant seedlings.
Warm season vegetables are tomatoes, eggplant, cucumbers, peppers and squash. These warm season plants are usually started from seed indoors in early March. Peppers are the exception. They can be started this month so the plants are a bit larger when they are planted out. Since we don’t have a long growing season it gives the plants a head start. I start all my tomatoes in early to mid March in the greenhouse. They are planted outside in mid May. Cucumbers and squash are best direct sown in mid May where they are to grow as they don’t like to be transplanted.
Let’s look at annual flowers. Again it’s best to grow from seed 6-8 weeks before your plants go outside. There are always exceptions to the rule but you will learn that as your experience grows. Yes, some flowers can be direct sown from mid April to late May so be sure to read the growing instructions on the seed package. Like vegetables some flowers are more cold tolerant than others. Cosmos, nasturtiums, snapdragons, marigolds, sweet peas and alyssum can be planted out in April by direct sowing. Flowers of Petunias, Coleus, Verbena, sunflowers and zinnias are planted in May. I generally recommend that annual flowers prefer a night time temperature of 10C consistently. Since we tend to have a healthy slug population, I grow most of my plants inside from seed. I find a larger plant often fares better against pest problems than a tiny seedling planted directly outside.
If you are starting seeds for perennial flowers do some research on each one before getting started. Most perennial seeds need a cold period in order to germinate. Perennial seeds can be planted in late fall or early winter as this allows the seed coat to soften over the winter. Some perennial seeds like clematis can take years to germinate so ask yourself if you want to wait that long. If perennial seeds are planted early enough in winter they may bloom the first year. Often they don’t bloom until their second year. They are definitely worth the wait if you want to save money. Starting plants from seed is so rewarding and can provide you with interesting varieties that you may not be able to buy at the garden centre.