The middle of January may seem too early to think about sowing seeds, but spring isn’t far away and we need to get ready now. Good preparation will help you to successfully raise seedlings and prevent problems. First, we need somewhere to germinate the seeds. Some will have to be content with windowsills or a sunroom. Here it’s relatively easy to maintain warmth for germination but light levels are low so seedlings can get stretched and straggly.
Fortunately, indoor growing lights or strips of LED lights are now easy to buy and fix above the plants. In a greenhouse the problem is providing warmth. If there’s electricity you can heat a small area for growing seeds with a heated propagator, heat mat or sectioning off an area to heat. Seedlings only grow well if the balance of heat and light is right. Most seeds will germinate in a temperature around 18C (65F) or slightly higher.
Few seeds need a temperature above 27C (80F) and too much heat can cause straggly seedlings or even prevent some from growing. Seedlings are prone to diseases so always use fresh compost from closed bags, and make sure that all trays and pots are either new or have been washed. Have some Perlite or Vermiculite ready to add to the compost to improve drainage – and some labels so you can keep track of what the seedlings are.