harden off those youngins


Greenhouse seedlings at SHARE Food Program || photo by Lauren Mandel

With spring upon us, greenhouses across the country are full of eager seedlings.  Sheltered greenhouse environments are ideal for sprouting seeds and providing a head start for young veggies, but the real growing occurs outdoors.

Before transplanting seedlings to nearby raised beds and agricultural plots, the youngins need to be “hardened off.”  This involves acclimatising the seedlings to the sun, wind, and variable temperatures they will experience outside.  Farmers have different strategies for hardening off their plants, which usually involves introducing seedlings to the elements gradually.  Farmers may move young plants in and out of a greenhouse, leaving the seedlings outdoors for longer periods each day.  This gradual introduction often lasts for one to two weeks.

When moving seedlings to rooftops, extra care must be taken in hardening off the plants.  As discussed in earlier posts, rooftop environments are much more extreme than their ground-level counterparts.  Skyline farms and gardens are prone to high winds, desiccation (soil drying), and fluctuating temperatures.  So what does this mean for the hardening off process?  Well, the plants should probably be exposed to stronger elements.  This could mean leaving them outside on a particularly cold and windy night, or even bringing them up to the roof for short periods before transplanting.

Anticipating scenarios such as hardening off can help to inform the design of a rooftop farm or garden.  Enough foresight could lead to the construction of a sheltered rooftop area, designed specifically for acclimatizing seedlings.

What techniques do you use to harden off your youngins?

Leave a Reply

%d bloggers like this: