As our days shorten and the sun sinks lower into the southern skies, lack of sunlight can cause some sun-loving plants to not to receive all the light they need to properly grow and flower.
Reduced light most commonly affects houseplants. Plants growing in room interiors far away from windows may become light-deficient. The first indication may be a yellowing or drooping of leaves throughout the plant. Plants craving light often stretch out for it, creating long, spindly growth. Usually compact plants become thin and leggy, developing long spaces between leaves. Flowering plants stop flowering. As conditions worsen, plants become stunted and simply stop growing.
Placing houseplants near an artificial light source during the evening hours can be used to increase light exposure. Plants can be placed close to fluorescent lights, but keep them back a foot or so from incandescent bulbs, because the heat produced can burn the plant. When germinating garden seedlings indoors, use a combination of one cool white and one warm white fluorescent tube in a single fixture. This combination provides the best reproduction of natural sunlight and is a lot cheaper than buying full-light spectrum grow lights.
Just as plants indoors may not be receiving enough light in north exposures, the same holds true for container plants on north-facing patios. It may be necessary to move highlight-requiring plants such as container-grown hibiscus to east-facing windows, or closer to west- and south-facing windows that will provide additional light.
When possible, move container plants to areas receiving at least six hours of direct sunlight per day. Just moving pots farther out from the house, away from the heavy shade created by northfacing house walls and overhangs, will help. Longer periods of brighter indirect light can compensate for the lack of direct sunlight. When planting vegetable and flower beds, always locate taller-growing plants on the north side so that they do not block sun from lower-growing varieties.
Flowers that bloom well in shade conditions include pansies, impatiens, begonias and coleus.
Evergreen trees casting too much shade on patio plants and winter flower or vegetable beds can be pruned to thin growth and allow more sunlight through. Thinning is the selective removal of some stems and branches throughout the tree’s canopy. Cuts should always be made at the crotch with another branch or the main trunk. Wait until mid-December for heavy pruning. While temperatures are still warm, pruning can stimulate new growth that is cold-sensitive and easily damaged by frost and freezing temperatures. The exception to this thinning procedure is citrus. Do not prune citrus trees to thin growth, because the bark of citrus trees is sensitive to light. Exposing the trunk and branches to strong sunlight can cause the wood to sunburn and die.