Spring 2012- seedling cultivation

I have sensed a weather pattern over the past decade or so that gives us an over-warm and early spring, which is then followed in June/July by a nondescript "summer" and occasionally a late warm spell in September or even October. This year started off true to this new pattern, with a very warm period in March but then reverted to cold weather in April. These stop-go-stop changes in our weather don't make life easy for gardeners. And Spring 2012 featured particularly sharp contrasts in temperatures and contrast between hot sun and very cold air from the east.

Spring chaos in the greenhouse

Autumn-sown endive and transplanted strawberries 

This year I was particularly well-organised, with potatoes chitting and many seeds sown in January. The warm March spell reinforced this precocious start. Thus by March my tomatoes were well-advanced- around 3" tall, indoors and ready to move to their new home in the greenhouse. Then came winter again! A similar false start afflicted my potatoes which were all in the ground by the end of March. Although I have been cautious with planting too early in the past, I played safe this year and fleeced most of the rows- but still nearly got caught out with a late frost in mid-April when the first fleshy leaves were fully exposed!

I have, over the years developed a sequence of stages for bringing on my plants. I sow in trays or modules of potting compost, water well and enclose in a large plastic bag. This holds in the moisture and retains some heat. Later, when being hardened off, it also protects from the wind or cold air.
I then keep these trays in a warm room indoors. Certain seeds, notably aubergine, peppers etc need around 70deg to germinate- so a warm place to get them out of the ground is vital. Keep a close eye on them as, as soon as the stems appear they will go go very leggy if not kept in good light conditions- a window ledge is not usually sufficient.
For this purpose I suspend the seed trays immediately under our Velux windows where the new seedlings get maximum natural light. At this point I have
removed the plastic bags

Seedlings in the light

Having only limited space of this kind, many of the protected trays will go in the greenhouse during warm days to get full benefit of the heat and light, and brought back in at night
One note of caution-- if using the bag-covering system, make sure the soil doesn't get too damp or wet or damping-off will be a risk:
some seedlings are more vulnerable to this than others.

Obviously, during this process, I will transplant seedlings from modules or trays into individual pots as they outgrow their environment.