Container Garden Bounty: Growing Vegetables and Herbs
If you grow vegetables in the ground, you know that the No. 1 rule is to keep them racing along — with plenty of water, fertilizer, sunlight, and whatever else the specific crops require. Vegetables and herbs in containers are no different. In fact, providing the essentials to vegetables and herbs growing in containers can be more challenging because their growing space is limited. To ease the caretaking task, container plants can grow right outside your back door where you can dote on them. When you know what it needs, your portable garden is likely to reward your attention with tasty returns!
The right container
First question: Are you growing vegetables and herbs for show or just production? If all you want is to pick the produce and you don't care what the container looks like, requirements are pretty basic.
The container must be big enough. A minimum size for most vegetables and herbs is a diameter of 8 inches and depth of 12 inches, but a diameter of 12 to 18 inches and a depth of 15 inches is preferable — the larger size can accommodate the necessary volume of soil and water. And the container must have drain holes at the bottom. Vegetables and herbs can be found thriving in all sorts of containers that meet the size and drainage requirements, but that miss the boat in beauty: leaky buckets, garbage cans with holes, large plastic buckets from delicatessens, and even plastic milk jugs.
If the containers are going to be part of your garden scene, you probably want something more presentable (but with the recommended size and drain holes). Remember that terracotta, no matter how attractive, tends to dry out quickly — a major problem for vegetables and herbs racing full steam ahead. You may be better off planting in plastic. If you want a big container to hold a number of vegetables and herbs or a whole salad's fixings, an oak half-barrel is hard to beat.
Commercial soil mixes can be used straight from the bag. But many vegetables and herbs benefit from additional organic matter like bagged compost or ground bark: Add one part of organic matter to each three parts of soil mix.
In general, vegetables and herbs are heavy feeders — especially when grown in containers. Nutrient needs vary according to what you're growing. Lettuce and other leafy crops need nitrogen to produce those leaves, whereas tomatoes need some nitrogen to grow, but too much can inhibit flowering — no flowers, no tomatoes.
As a general rule, add an all-purpose dry fertilizer — organic or chemical — according to package directions when you plant. Organic fertilizers release their nutrients slowly; chemical fertilizers release all their nutrients at once, unless you pay a lot more and get the slow-release kind.
As container crops are growing, fertilize regularly, following label directions. Most people prefer to use a soluble fertilizer applied as you water. Some gardeners swear by fish emulsion — smelly for a while but not likely to burn or overfeed.
Water, water, water
Watering is always important with container plants, even more so with vegetables and herbs — let them wilt once and they may never really get back on track. Containers can dry out in a day or in a few hours depending on the planter's size and intensity of the summer heat; rewetting a dry pot may seem impossible. To avoid the problem, check pots and planters often and do not allow the soil to dry out more than an inch or two below the surface.
Experienced tomato growers know that if watering is not consistently maintained, tomato plants are unable to take up calcium, a much-needed nutrient. The result is tomatoes with a dark, leathery spot on the blossom end (the bottom). The telltale coloration doesn't signal a disease, and there's no magic spray to fix it, so pay attention.
Along with watering, sunshine is the other limiting factor in vegetable and herb gardening anywhere. Most vegetables need a minimum of six hours of direct sunlight — that is, sun on the plant, not somewhere nearby. Exceptions are lettuce and spinach, which actually benefit from some shade in the heat of midsummer to keep them from bolting — sending up flower heads that end your salad-picking days.