The growing season at our Pebble and Fern gardens is quite short. This is a fairly cold-Wintered area (cold-Summered too, sigh). To get a good yield of the vegetables that need more frost-free days than our climate permits we have to start many different plants indoors on sunny window-ledges and under artificial lights.
This gives us a batch of rather lovely out of season “hot-house” babies that need to be acclimatized to much harsher outdoor garden conditions.
Late April is the time when hardy and half-hardy seedlings must be prepared for transplanting. This process of getting the seedlings ready for transplanting is called “Hardening Off”. It involves increasing exposure to wind, full sun and also to some level of cold, depending on the hardiness of the seedlings in question. Hardening off is a fairly simple process but it is also a somewhat lengthy one – a couple of weeks of gradual exposure are needed before a house-grown seedling is ready for the rigours it will face in the big garden.
Basically, give your little plants increasing doses of outside air and decreasing amounts of heat. Start the hardening off process on a warmish day and put your little plants out for a few hours in a shady and sheltered spot. Each subsequent day lengthen the time that your plants stay out and expose them to more hours of direct sun. Watch your plants for signs of stress and put them under shelter as soon as leaves appear to wilt. You want to toughen them up gradually and not to windburn, sunburn or stunt them. A little bit of insect cloth or tulle fabric can be helpful as you take your plants through the toughening up process. Use it for a make-shift windbreak or as a bit of shade on a really sunny day (not that we get all that much hot sun in April here, but you never know).
In the same vein withhold watering and keep the plants that are being hardened off a little on the dry side. Failing to harden the little plants off thoroughly before transplanting can often be fatal so this process must be taken quite seriously. Ahem. At the end of the hardening off period your plants should be outside all day and inside only at night. Follow this with a couple of full days and (warmish) nights outside before transplanting seedlings into their final spots. Phewf!
It is quite a pleasure to see the trays of lovely green seedlings getting a dose of sun and air. The rest of the garden beds still look something like soggy bomb craters (it even snowed a little bit last night!) so the promise that the little Kale, Lettuce, Cabbage, Onion, Artichoke, Celery and Swiss Chard seedlings will soon become a garden is very welcome indeed.