Sow and Grow
Growing plants from seed is a very economic, interesting and rewarding hobby. It allows us to experiment with unusual varieties but for success we need to understand the conditions various plants require for guaranteed germination from the humble Radish to the exotic Bird of Paradise Plant (Strelitzia).
It is important to have space to accommodate the germination pots and trays so a heated propagator and grow lamps in a heated greenhouse or conservatory is ideal but costly in terms of energy. A spare room in the house with background heat and propagators on window sills is more energy efficient.
Timing is vital so if you have the ideal facilities to grow on the young plants you can sow some species like Begonia, Geraniums, Peppers and Chillies as early as January. Otherwise most success is achieved by sowing your seeds in April when the temperatures are rising, the days are lengthening and light levels are high. Or buy these plants from the Garden Centre at the beginning of May.
It is important to have clean equipment so wash everything in a dilute solution of Jeyes Fluid or hot water. I recommended you use plastic pots or trays which retain moisture better than terracotta. Fibre pots and Peat pots are also useful for germinating large seeds like Sweet Peas, Cucumbers, Melons and Sunflowers. They can then be planted directly into their final position without transplanting.
Temperature is a very important factor for good germination. Seeds like Primulas need one week at 24c then 20c degrees. Conversely lettuce will not germinate above 20c. Broccoli Cabbage and Cauliflower need 10c to 15c while Geraniums, Begonias and Impatiens need a constant heat of 22c to 25c degrees.
Peas, Broad Beans, Onions, Beetroot, Carrots and Parsnips and hardy annuals like Nasturtiums, Cornflower and Poppy are sown directly outdoors from April, thinly, into soil that has been raked to a fine tilth. For root vegetables sow the seeds 4cm apart to avoid disturbing the roots by thinning. The soil temperature needs to be about 8c. If very cold nights are threatened cover the planting areas with fleece which will keep the soil and seedlings warm.
It is important to use a good quality compost to germinate seeds. Jacks Magic is a fine peat based compost which retains moisture essential especially for the fine dust like seed of Nicotiana or Gloxinias. Westland Seed Compost is also recommended. It has added nutrients to produce strong growth in the young seedlings. Fill the containers with compost and then water. Allow the water to penetrate the compost and tamp the surface to level and smooth. Don’t be tempted to sow all the seed in the packet. Think how many plants you actually need and sow 10% more seed thinly on the damp compost. The sowing density should allow the seedlings to germinate and grow so there is room to produce the two first leaves. Most seeds should be covered with a fine layer of compost or vermiculate and then with a clear propagator lid to aid germination.
Most tender varieties of flowers or vegetables should not be planted outside in the Borders, Veg Patch or Patio Pots until the end of May to ensure the young plants are not exposed to cold nights and frost so sowing most seeds about the beginning of April is recommended unless you have good heated greenhouse facilities for holding and growing on young plants.
For tender varieties of flowers like Petunias, Lobelia and Marigolds and Vegetables like Courgettes, Runner Beans and Sweet Corn use cell trays or pots filled with good quality compost. Moisten the compost and put a single large seed or a small pinch of fine seed into each cell or small pot and then vermiculite on top. Cover with a propagator lid, dome cloche or polythene bag and put in a warm place indoors or in a heated propagator in a greenhouse until the seeds start to germinate. Move to a good light source, a warm windowsill if growing indoors, until the seedlings are large enough to handle, usually when there are more than 2 leaves. Transplant the seedlings into larger individual cell trays or pots to grow on until planting in their final position at the end of May.
I am sure you will find “Sowing and Growing” your own plants will provide a very rewarding and interesting pastime save a lot of money.