Greenhouses and window greenhouses
Heated greenhouses are probably best for starting seeds indoors. Chilli-heads fortunate enough to have a greenhouse enjoy plenty of diffused sunlight, heat from both solar gain and heaters, humidity created from other plants, and air circulation from fans. However greenhouses also have a few drawbacks. Some greenhouses, especially those attached to the south side of a house, have low light duration and levels, causing the chilli seedlings to become leggy and topple over. In this case, the newest growth of chilli seedlings may need to be pinched back to cause outward growth and produce a bushier chilli plant.
Some greenhouses, in particular north facing ones, may overheat during the spring and might need some shading. Greenhouses also need adequate ventilation to avoid problems with damping off and stem rot.
There are a lot of chilli heads that suggest windows are a good place to germinate chilli seeds and to grow seedlings, but this is simply not true. The amount of available light decreases through the window as the sun rises higher in the sky and the day’s approach the summer solstice, resulting in spindly plants. Cats are another problem with windowsill cultivation, because they are notorious seedling grazers and can quickly destroy your freshly sprouted chilli crop. Cold drafts at night and inadequate air circulation during the day also causes problems.
Window greenhouses that extend outside the house are much better than windowsills because they provide more light. However they cooldown at night so heating cables should be used under the pots. Unfortunately, window greenhouses lack the space to grow a large number of seedlings and they tend to trap hot air, so they need to be well ventilated. However if used carefully, they are fine for the chilli-head growing only a few favourite chilli plants.