Spring Seedlings

Seedlings that are grown on windowsills, under lights or in greenhouses have soft stems and tender leaves. They have to be 'hardened off' before they are planted outside. This means to gradually get the delicate plants used to outdoor conditions; direct sun, wind and cool nights.

Transplanted seedlings in the sun room

Last week my first seedlings were transplanted from flats into 4" pots ...tomatoes, herbs and broccoli. I have staked each tomato plant with a skewer and twist tie to support them in any wind. The newly transplanted seedlings were kept in a cool, shady place for a few days to recover from transplant shock, then moved to a brighter location. I will start hardening them off soon. The process is simple; the first day place the plants outside in the sun for an hour or a bit longer if it is cloudy, then move them back inside for the rest of the day. Over a span of 7-10 days, expose them to direct sunlight for longer periods until they are outside all day. Hardening off tender crops like tomatoes, cucumbers, squash etc. mainly means getting them used to direct sunlight. These tender crops can be seriously set back or even die from sunburn if they are abruptly moved from indoors into full sun for a whole day. A cold frame is ideal for hardening off plants but be sure to open the cover for ventilation. Each day open it a little more so by the time the plants are ready to be set out, they are used to the sun and outdoor conditions. 
With our fluctuating spring temperatures, if it is not warm enough to plant seedlings outside, be prepared to move them to larger pots if they become root bound. To tell if a plant is root bound; look for excessive roots coming out of the drainage holes or if you cannot get the root ball to easily slide out of the container.
Once the garden soil warms, the ideal weather for transplanting your hardened off plants is a cloudy day. A hot, dry day will increase the shock of transplanting. Also, if you have left the seedlings in flats, they will take longer to recover than those grown in individual pots because their roots will suffer more damage during transplanting. When transplanting tomatoes, plant up to the first leaves because every hair on the stem will become a root. Once planted outside, protect the plants from the sun and wind for 3-4 days to give them time to recuperate. I use an assortment of materials; cloches covered with remay cloth (floating row cover), plastic mesh trays propped up with a stick and tomato cages draped with burlap. The object is to shade plants from the midday sun until their roots recover. If a cool spell threatens, try covering plants with cloches, plant pots turned upside down or floating row cover to keep them warmer. 
Till next week, Happy Gardening and Bon Appetit!


Photo by Sally Rae