Whether you use fresh herbs for cooking, crafting or for their healing properties, taking proper care of your herb plants guarantees healthier and bigger plants that produce more for the entire season. Once established, taking care of herb plants takes little time and is well worth the effort.
No plant can live without water and that certainly includes herbs. Depending on where you live, you may rarely need to water your herbs because Mother Nature provides plenty of rain. In other areas, you may need to provide water daily in order to keep your herb plants healthy. If your herbs are in containers, you will need to be especially mindful of their need for water, especially if they receive hot afternoon sun.
Herbs don't need a great deal of fertilizer to provide healthy leaves and roots, but a dose of garden fertilizer (5-10-5) in the spring and the fall will benefit them. Garden fertilizers are listed with nitrogen, phosphorus and potassium percentages; 5-10-5 means 5 percent nitrogen, 10 percent phosphorus and 5 percent potassium.
The nitrogen (N) in fertilizer will help boost growth of the leaves and roots by assisting the plant in virtually every function, including water uptake. Phosphorus (P) promotes root development and early maturity, and assists the plant in storing and transferring the energy it requires. The third ingredient, potassium (K), is required for photosynthesis and a deficiency produces smaller, less productive plants.
You don't want to over-fertilize your plants, which can cause havoc. There are soil tests available that allow you to check your soil before applying fertilizer, which may not be necessary. Container plants are more likely to need fertilizer than plants in the ground.
Since you could be planning to eat your herbs, you don't want to use chemicals to combat pests, like mites or aphids. Fortunately, many herbs are naturally pest resistant because of their taste, smell or texture. Also fortunate for herb growers is that you can make a spray from your herbs to spray on other plants that are being pestered. Pour four cups of boiling water over the leaves of chamomile, elder leaves, rhubarb leaves, basil leaves or two garlic cloves, and let the mixture steep for 10 minutes. Strain, cool and pour the water into a spray bottle. Alternately, you can purchase Pyrethrum spray, which is made from the dried flowers of pyrethrum plants, or Rotonone, which is made from the roots of a legume in the tropics.
Check under the leaves of your herb plants for microscopic pests that could be eating your plants, and treat them immediately with a spritz from your organic insecticide of choice.
Plants have a natural urge to produce flowers, which in some cases is not the desired result. Some herbs, like lavender and monarda (bee balm), should be encouraged to flower. Others, like most edible herbs, will put their energy into producing flowers, and the leaves will toughen or become bitter. As soon as you notice a bud-head forming, pinch it off with your fingertips to signal the plant to keep producing leaves and roots. Seeds are the desired end result for dill, cilantro (which becomes coriander seeds), fennel, lovage and caraway, so ignore their buds and blooms and let them grow.
Oregano and all the various members of the mint family can become invasive if given the chance. Their root systems are strong and are capable of crowding out other perennial herbs nearby. You might consider growing these in pots or in another area where they can freely grow, or you can work at keeping the new plants pulled as they emerge.