Growing Herbs in a Container
By Brian S.
Like root, leaf and flesh vegetables you can create a container herb garden on your deck, balcony or front steps. Due to their hardy nature, herbs such as rosemary, parsley and basil are probably the easiest and most perfect plants to grow inside a container. Growing an assortment of herbs in a container means you’ll be able to step outside your door and pluck a handful to spice up your meals, perk up your tea, or jazz up your salads.
Soil & Pot Depth
Whether you plant seeds or purchase live plants from a nursery, all herbs do well in a crowded environment, with the exception of basil which requires a little room for good air circulation. Otherwise, you can grow as many different herbs in a single container as you wish. Before planting, you need to ensure that all the herbs destined for the same container share the same sun, water and soil requirements. For example, rosemary likes it hot and dry while parsley prefers a diet of steady moisture. Therefore they should not be paired up in the same pot. As a rule of thumb, you can plant herbs according to their type. Italian herbs like basil, oregano, parsley, sage and rosemary all get along well. Aromatic herbs, such as sage, lavender and chamomile are all well-matched. While the similar needs of beverage herbs like spearmint, peppermint and chamomile are good bed fellows.
Herbs grow best in a ‘lean’ soil that drains well. That means using a loose, soil-less “potting mix” rather than a dense and clingy “potting soil”. Because herb plants don’t have a large root system, they are well suited for shallow and smaller containers. This is especially true when it comes to seasonal or annual herbs which die and must be replanted each year. Perennial herbs can survive year-round in a container. The depth of the container isn’t as important as the size. Small containers will suffice for a single or annual herb plant, but for multiple or perennial plants – three to five gallons of soil is recommended. Any type of container will do, but it absolutely must have adequate drainage so excess water will drain away.
Water herb plants only when the top soil feels dry, but don’t let it dry out completely in between watering. Stick your finger into the soil. If it feels dry one inch beneath the surface, the plant needs water. If you over-water, the container will become waterlogged and deprive the roots of oxygen. Pour water directly onto the soil until it begins to run out of the drainage holes in the bottom. Avoid wetting the leaves as this will encourage mold and other diseases. In general, smaller containers need more frequent watering than larger pots because they contain less soil and dry out faster.
Herbs require a minimum of six hours direct sunlight and do even better when exposed for eight hours. To optimize growth, place the containers in the sunniest location you can find or move them to follow the sun each day. If the temperature really soars place your containers in a shady spot during the hottest hours.
Believe it or not, most herbs thrive on a certain amount of neglect. So don’t over-fertilize your herbs because they don’t like it. Some horticulturists claim fertilizing should be avoided altogether. That rule may be applicable for herbs when they are grown outside in a garden or field where nutrients can be drawn from the ground, but when grown in containers, regular watering will wash the nutrients out of the potting mix. To replenish the lost nutrients, mix a water soluble fertilizer at half strength and apply it every three weeks or so when you water the herb plants. To guarantee you’re not over-fertilizing, leach the excess fertilizer out of the soil once a week by applying plain tap water until it runs from the bottom of the pot.
Keep an eye on your herbs as they grow and remove any dead or diseased leaves from both annual and perennial herb plants. Leafy herbs are ready for harvesting when their leaf growth reaches its peak or as soon as flower buds begin to appear.
When harvesting annual herbs which only grow for one season and then need to be discarded, always leave a minimum of at least four to six inches of the plant. That way the shoots will re-grow and can be harvested again before the end of the growing season.
When it comes to picking perennial herbs which grow year after year, do it less aggressively. Try to cut or pinch off only the leaves you need each day. That way you will prevent the plant from blooming. If you let the flowers blossom the herb’s flavour will be diminished. Harvesting only a daily quota of leaves will promote fresh growth and keep the plant bushy all year long. Never remove more than thirty percent of a perennial plant’s leaves and stems. Once collected, the harvested herbs can then be consumed fresh or dried for future use.