Sally Petitt is the Head of Horticulture at Cambridge University Botanic Garden where she supervises a team of 17 permanent horticultural staff across the Garden’s eight horticultural sections, and seven trainees. She began her career at the Garden as a horticultural trainee and also oversees the Garden’s trainee programme.
For me as a gardener Spring brings with it a sense of anticipation and excitement for the coming year. No gardening activity reflects this more than growing plants from seed. For some this can present a challenge, seeming too fiddly and complicated, and requiring a range of specialist equipment. But it doesn’t need to be a complex or mysterious task, and can reward with a real sense of achievement. It can also be a cost-effective way to fill your garden, with a packet of seed, compost and pots, being far cheaper than one plant bought at the garden centre. If this isn’t enough to entice even the most novice gardener to give it a go, it’s worth adding that nothing can beat seeing freshly sown seedlings nudging their way through soil or compost- something which always brings me a sense of awe and wonder! No matter how many times I sow seed I never fail to be thrilled by those first emerging seedlings, knowing that in some small way I’ve aided this process on its way.
There are many plants suited to launching you on your plant propagation journey without the added requirement of specialist equipment, such as heated propagators and greenhouses. Here are a few: Broad beans (Vicia faba) and sunflowers (Helianthus spp.) can be sown directly in the garden into a clean, prepared bed. Flowers such as love-in-a-mist (Nigella damascena) can be thinly scattered over the surface of a fine tilth (freshly prepared and finely raked soil) in the garden and in just a few weeks, will bring months of joy! Some plants, such as tomatoes require a little bit more input, and these should be thinly sown in a small pot in fresh seed compost and covered lightly with compost, and gently watered. The pot should be covered with a polythene bag, secured in place with an elastic band, and then placed on a windowsill, with the soil kept moist. After a week or two you will see seedlings breaking through the surface of the compost. Once the first leaves are large enough to handle you can prick the seedlings out into individual pots or modules in potting compost, and grow them on the windowsill until large enough to harden off outside in warmer temperatures before planting out.
Here at Cambridge University Botanic Garden, we grow many thousands of plants every year from seed, including easy annuals such as sunflowers, to herbaceous perennials, trees and exotic, tropical plants. While this requires great skill and patience, the benefits can be seen throughout the Garden and in some cases enjoyed for many years. It’s worth remembering though that even the most skilled suffer losses at the propagation stage, but the successes far outweigh the failures.
Top Seed Sowing Tips
- Read all instructions on the seed packet – this will give advice on sowing conditions, including temperature, depth and distance between seeds.
- If sowing outside check when weed seeds start emerging – at this stage the soil and weather are good indications that conditions are right for seed sowing.
- When sowing in pots be sure to sow seed thinly to minimise competition and encourage strong, healthy growth at an early stage.
This piece was originally written for Cambridge Edition magazine.
