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Gardening Basics 1: Understanding Light Conditions

by Tammie Painter

garden light

The health of any garden starts with keeping plants in their proper growing conditions. Trying to grow plants in the wrong soil type, soil pH or light quality will turn even a low-maintenance species into one that requires extra work and extra resources to help it survive.

An understanding of three planting conditions that strongly affect your garden’s health will keep your plants thriving and allow you to solve problems when they arise. This post, the first of three in a series, will cover light conditions.

Key condition #1: Quality of light
Light is one of the easiest planting conditions to determine. Most plants come with tags stating their light requirements; if they don’t, you can easily find the information online or in a book. To figure out your garden’s light conditions, you only need to look out your window during the growing season.

Botanically speaking, light requirements range from full sun (at least six hours per day), partial sun (four to six hours per day), partial shade (one-and-a-half to four hours per day) or full shade (less than ninety minutes per day). Timing also matters. Some plants—coral bells (Heuchera cvs.) and false spiraea (Astilbe spp.), for example—tolerate full morning and evening sun, but cannot withstand direct afternoon sun in summer.

A plant that receives too much sun quickly suffers. No matter how much you water, the plant appears wilted even after the sun goes down. Leaves may turn yellow from sun-bleaching or from overwatering. If shade isn’t provided, the plant grows poorly and the leaves drop off or burn, eventually leading to the plant’s death.

On the opposite end of the spectrum are full-sun plants in too much shade. As they stretch toward any light available, these sun lovers grow tall and lanky with distorted leaf development. Because many plants rely on light cues to bloom, any plant in the wrong light conditions will fail to flower well and fruiting will be less productive or non-existent.

The solution is fairly simple: Observe your garden before you fall in love with a certain type of plant. If the sun blasts your garden beds most of the day, a fern garden dotted with hostas and hellebores will not work. Likewise, if your garden leans toward the shady side, dreams of a cactus garden should be reconsidered.

When not tending to her shady garden in Portland, Ore., Tammie Painter creates botanical art and writes full time. She is the author of several books, including Going Native: Small Steps to a Healthy Garden.

Image credit: Carlos G. Lopez/Moment/Getty Images