Wednesday May 26 2010
Ask the Master Gardener: Vegetables need adequate sunlight
By: Trish Grenfell Placer County Master Gardener
Question: I have a small backyard with no place that receives a full six hours of sun. I have been told that I cannot grow a vegetable garden. Is that true? Answer: Space-challenged gardeners have been trying to maximize the conditions they have and some have been quite successful. That being said, a full six hours of sun and rich soils are the ideal conditions to grow vegetables. And no vegetable grows in full shade. So how much sun do you have? Clock it now but remember that the sun hits the garden area at different angles as the seasons progress. You can add up the hours of sun over the course of the day, especially if it is unobstructed. And if you grow vertically or hang containers from a high post, you may be able to catch additional sun rays. For shade gardening, you can break vegetables down into three categories: fruit, root and foliage. Plants from which we primarily harvest the fruit, such as tomatoes, melons, peppers, eggplants and squash, require the most sunlight and warmth. Optimally they like eight to 10 hours of sun. It’s probably unwise to attempt growing any of these if your site receives less than six hours of sunlight a day. Vegetables grown primarily for their roots and flowers require a little less. If you have as much as four hours of sun, it may be worth trying to grow radishes, beets, carrots, broccoli, Brussels sprouts and cauliflower. With as little as three hours of sun, you may successfully grow leafy vegetables: lettuce, endive, cress, radicchio, arugula, spinach, kale, chard and mustard greens. These plants tolerate partial shade quite well because they can be picked at any stage of maturity. Remember that your resulting garden will have thinner leaves and will be less robust, but they will be tasty even though their growth is not luxurious. In some ways, growing in a site with part shade is easier than growing in full sun. You won’t have to water as often, and crops that are quick to bolt (flower) in hot weather, such as lettuces and spinach, will grow quite a bit longer given some shade. However if your garden is under trees, you will encounter issues with inadequate water and soil fertility. The tree roots are greedy and you must find the right balance for additional water and fertilizer. Remember that the tree cover also reduces available moisture from rains. Even if you’re lucky enough to have a garden area with full sun, knowing which plants will take some shade will help you maximize your property for vegetable gardening. Have gardening questions? Call the master gardener hotline at (530) 889-7388.