Updated on December 18, 2024 by Ruth
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Growing basil can be a rewarding experience, but even for seasoned gardeners, keeping these herbs alive and thriving can sometimes be a challenge. Basil is known for its aromatic leaves and versatility in the kitchen, but it can also be quite finicky, requiring specific care to ensure its health and longevity. As seasoned farmers, we’ve learned a few tricks along the way to help basil thrive. In this guide, we’ll share our top tips and tricks for growing happy, healthy basil plants all year round.
Table of Contents
Start from seed or buy a plant?
It’s not difficult to start basil from seed, but it does require extra attention in the early stages and specific growing conditions. Keep the soil slightly damp until the seeds sprout. Basil seeds like warm soil, at least 70F, so unless it’s consistently warm outside with nighttime temperatures above 70, you will start the seeds indoors. We use a germination mat, which provides a low level of warmth under the tray to warm the soil. Warmer soil means the seeds germinate more quickly.
Once the stem and leaves appear, you have a delicate balance of enough water but not too much water. The young seedling can dry out easily, but too much water will cause it to wilt. The goal is to let the soil become almost completely dry each day and then add more water. Try to avoid getting water on the plants themselves.
Once the plant has at least 4 true leaves (the first two don’t count), then you can transplant into a larger container or, if it is warm enough, outside. Remember, basil likes warm temperatures, not cool.
If you buy a plant, then the farmer has done the starting work for you. Look for a plant with a sturdy central stem, but not hard. You do not want any black spots on the stem. That is a sign of too much water, and the black areas will spread throughout the whole plant.
Can basil grow from cuttings?
Basil is one of the easiest herbs to grow from a cutting. Take a stem of basil that has at least two sets of leaves. Trim ¼ inch from the bottom of the stem, and detach the lowest set of leaves (enjoy them in a recipe) and put the stem in clean water. Change the water every 2-3 days. Aim for water that is room temperature. Roots will develop in a week at the spot where the leaves were growing. There are root nodules at each point where leaves grow. Once the roots are a couple of inches long, you can take the plant out and put it in soil.
Ready to plant?
The number two reason why basil plants fail is they get put outside too early. (The number one reason is in the next section!) Always keep in mind that basil plants like warm soil and warm air temperatures. Aim for consistent nighttime temperatures above 55F.
Most basil plants come in a small pot which is fine for a seedling but which your plant will outgrow quickly. You can plant your basil in the ground or re-pot into a larger pot. How large your basil grows depends on how much space you give the roots to grow and how much sunshine your basil will get.
If planted in the ground, be sure that the basil plant is higher than the area around it, by about an inch, so that the water can drain off. If your basil is in a pot, the container needs to have holes in the bottom so that water can drain out as needed.
How much sun do basil plants need?
Basil thrives best in full sun, from sunup to sundown, and it thrives in hot temperatures as long as it has consistent water on the roots. Basil can grow in 4-6 hours of sunlight, but you will find that the plants do not get as large. For the greatest leaf production, let your plant get as much sun as possible.
How much water?
The number one reason that basil fails is due to too much water. Too much rain or overzealous watering by an anxious plant parent will cause your basil to develop black spots or a black stem and then fail. Basil likes to have the soil dry out in-between watering. Good drainage, whether in the soil or in a container, is essential. The water has to be able to drain away from the roots.
When the plant is getting too dry, the leaves will droop. This is the basil telling you, I need water! Can your basil plant revive? If you water the plant right away, it will recover. It is best to water before the leaves start to droop. In the hottest part of the summer, you will need to water more frequently.
It is very difficult for basil to deal with too much water, particularly if your area has rain for several days in a row (this can set up mold issues), or a deluge of rain which cause the basil to sit in water (the roots need access to air). If your growing area is prone to excessive rain, then you might want to plant in containers so that you can put your basil in a protected area during those times.
We now grow basil under a clear cover, called a high tunnel, at all times to protect the basil from the rain. This means the basil receives sun all day, we water the roots on a regular basis, and the leaves stay dry.
Harvest those leaves
It’s important to harvest basil leaves regularly, especially as the temperatures rise. Hot weather can make the basil “bolt”, which means it will start to produce flowers and seeds. While the flowers and seeds are still edible, as are the leaves, the stems thicken and become hard. The stems are not desirable for eating, but you can still use the leaves, which now have a stronger flavor. Regular harvesting keeps the plants in a state of producing more leaves.
If you harvest the leaves once or twice each week, pinch or cut at a stem juncture halfway down the stem, then you will be able to keep your basil plant producing for most of the summer. Each place where you harvest some leaves will now branch out, creating two stems for more leaves. The plant may possibly last even longer, depending on the weather. If you have rainy, humid weather, then your harvest time will be shorter.
Once temperatures drop below 50F at night, the basil decides it is finished and will not produce any more. If you want to bring your basil into the house, do so before temperatures drop below 60F so that the plant is not shocked by the change.
Grow basil indoors
Can you grow basil indoors? Yes, and it is a bit more challenging than growing it in the summer outdoors. Remember that basil loves sunshine and hot weather. Find a location that can provide at least 6 hours of sunlight daily. Do not have the plant too close to a window if the window panes get cold from the outside weather. That chill will affect your basil.
Check the leaves regularly, particularly the undersides of the leaves, to make sure there are no aphids. These will appear as tiny white spots on the underside of the leaf. You can use a damp paper towel to wipe them off and dispose of them.
Be sure to water the basil sparingly and only water the soil. Let it dry out in-between waterings. Too much water in the soil sets up a humid environment which can result in bacterial leaf spot (black spots on the leaves), gray mold, or root rot.
Basil can be a bit tricky to grow indoors, but the joy of having basil all year can be worth it.
Conclusion
The weather is beyond our control; if we could, we would fix the weather so it is sunny, warm, and gives us moderate amounts of rain. Make sure your basil can dry out between waterings. It is always fine to start another plant or 2 for later in the season. We are farmers who grow for our retail market and CSA program, and we plan on a new planting of basil every 4-5 weeks for maximum production.
Have fun growing basil this year!
~ Ruth
Additional resources
If the whole topic of watering plants makes you nervous, I understand. There are many variables. Here is a comprehensive course on when and how to water: Learn WHEN and HOW to water your planters.
