Plants started in a heated greenhouse or pur-
chased at a nursery can be placed directly into a
cold frame for acclimation. Generally speaking,
cool-season plants can be started earlier, while most
warm-season plants can begin the acclimation pro-
cess around two weeks prior to the average last frost
date. When first introducing the young plants to di-
rect sunlight, a small section of shade cloth can be
used to limit exposure. Each day the gardener can re-
move the shade cloth for longer periods of time until
the plants are acclimated. Most plant varieties will be
fully acclimated within 7-14 days from when they are
14
first placed in a cold frame greenhouse. Once fully
acclimated, the plants can either be planted into the
ground or, if the cold frame is large enough to house
them, remain in the greenhouse for the growing sea-
son. In order to combat excessive heat, cold frames
that house crops throughout the summer will need
to be opened up or ventilated with motorized fans
on hot days. Most hoop houses and side-walled cold
frames allow a horticulturist to raise or remove part
of the glazing material to increase ventilation and re-
duce heat build-up.
www.GardenandGreenhouse.net
April 2018