Love fresh spaghetti sauce or pesto? Growing herbs indoors lets you have fresh basil and other herbs all year round! Sure, a nice 1 X 4 window garden getting at least 4 or 5 hours of direct light from a sunny window will give you something to pinch here and there. Gardens with mint, rosemary, bay leaf, savory, oregano, chervil, and thyme are some of the easiest to grow this way.
But what if you really need your basil...lots and lots of it? Basil and cilantro need just a bit more light, and really prefer 8 hours or more of direct light each day. In addition to this if you want fresh pesto, just a pinch here and there is not going to cut it. Here's what you can do about it.
The goal for growing herbs indoors is to use a vegetative light cycle (18 hours on), with at least eight or more of those hours being direct sun or bright artificial light. Whenever the light levels are low, give them a boost. Two or three fluorescent lights above your plants will greatly increase their growth rate and yield. You can grow enough basil for a few servings of pesto now and then, and still have enough fresh herb always at your fingertips.
Or, with a small metal halide light you would have a larger garden area with much better lighting, growth, and yield (compared to fluorescent lights). You could surely produce an abundance of any herbs you choose for your culinary and aromatic delights. Basil would take well to the bright conditions under a metal halide, as it is a Mediterranean, sun loving herb.
It has been said that some herbs grow better, or should be grown in, poor soil. The oils in herbs make them special. Very fast growing herbs often grow plain leaves and stems more quickly than they can produce tasty essential oils. Often you will hear "basil grows better in poor soil" or "your basil will taste better if you don't fertilize". What these people really mean is "don't grow your basil too fast" (sorry to pick on basil).
Growing herbs indoors in a container, it is a little different. The plant still needs some food to grow, and when that food runs out you will need to fertilize. However, as you will see in the next two sections, this is all taken into consideration together with the growth habits of your herbs.
To keep initial growth rates under control when growing herbs indoors, I use a soil mix with just enough nutrients to keep things looking healthy. Having a mix with too many nutrients can make vegetative growth difficult to keep up with. Mix 2 parts sphagnum peat to 1 part perlite, then add 20 percent worm castings to the mix.
You can find other soil mixes ←here
Adjust the pH of any mix using sphagnum peat moss by adding 1 teaspoon of hydrated lime for every gallon of soil mix. You can substitute peat moss with coconut coir or vermiculite, which do not need pH adjusting. Finally, I add 1 Tablespoon of kelp meal for each gallon of soil to add plant hormones and to give beneficial micro-organisms something to feed on (carbohydrates). Use this mix whenever you transplant into a larger container.
If you feel the top of the soil and it is dry, than you need to water. Another way is to pick up the container and check how heavy it is. When growing herbs indoors you need to have containers with holes in the bottom, and you need to add an inch or so of perlite or gravel to the bottom of each container. Your herbs prefer a quick draining soil. It is best to water thoroughly, but less often. Water the container until some water comes out the bottom.
When growing herbs indoors, you eventually need to begin feeding them. In a container, the roots are stuck in a small space and quickly mine it free of any nutrients, especially if you were going easy on the nutrients to begin with. After ten days in the same container, feed with half strength nutrient such as Maxsea 16-16-16. Repeat every two weeks.
If you really want to keep your plants healthy, I also recommend 10 ml/gallon Thrive Alive B1 and Maxicrop liquid seaweed in every drop of water you give to your plants. The B1 is vitamins and root hormones, and the seaweed is trace nutrients and plant growth hormones. This will help with essential oil production. Finally, water basil from around the base...it does not like water on its leaves.
As soon as the herbs have grown enough leaves to be pinched without affecting their growth, you can begin using some of the herbs. This is usually about 2 to 6 weeks, depending on the herbs. Herbs like basil are best when harvested before flowers open. You will get your highest essential oil levels when you harvest at the end of the dark period, assuming you do not leave the lights on 24 hours a day.