I have been Herb Gardening for over 50 years. For 22 years as owner of The Herb Garden, I have been involved in festivals, classes, and speaking engagements and have compiled a list of questions I’ve heard numerous times about Herb Gardening. These Herb Gardening FAQs should answer many of these questions and as new ones arise I will include them here as well.
What are the easiest herbs to grow?
My herb hasn’t grown at all in months, what’s up?
Is it true you can’t grow lavender in Florida?
Can I grow herbs inside?
Why do my herbs die?
Herbs like to be neglected, is this true?
Is it too hot to grow herbs in Florida?
When is the best time to plant Herbs?
My thyme dies, what am I doing wrong?
Why does my Cilantro always die?
How often should I water my herbs?
Why does my rosemary get black spots and loose leaves?
Why does my Basil get black spots and loose leaves?
Why does my lavender drop leaves and die?
Q: What are the easiest herbs to grow?
Growing all herbs is easy if you understand their growing requirements. If you do not know much about herbs, I’d have to say that the following herbs are some of the easiest to grow: Parsleys, Oreganos, Chives, Tarragon, and Mints. Certainly, there are many more, but it takes some gardening knowledge to grow them successfully. My class on Growing Herbs in Florida goes into detail on everything you need to know.
Q: My herb hasn’t grown at all in months, what’s up?
“What are you fertilizing the herb with?” would be my first response to this question. Often, the response is nothing, thinking the natural fertilizers in the soil are enough (i.e. leaves, organic matter, etc.). While this may be true in many cases, it takes a very rich, well-balanced soil to be the only source of food for a plant. Here in Florida, we have soils that are very sandy or those with a large amount of clay, both of which are lacking in natural organic matter and nutrition. As a result, an herb not only shows very little growth but also develops deficiency symptoms. You should know your soil type and apply a slow-release, organic fertilizer if your soil is poor. However, feeding the plant is not the only solution, and you should also consider building your soil up with compost so that you are feeding your soil and the soil will feed your plants in the end.
Q: Is it true you can’t grow lavender in Florida?
Not true at all! The key to growing Lavender is to understand its growing requirements – hot weather, plenty of sunlight, low humidity, and well-drained soil. Lavender also prefers an alkaline soil, like many other herbs. Because Lavender is high in essential oils, the transpiration rate is slower than most herbs. As a result, Lavender struggles to get rid of soil moisture during our rainy summer months of July, August, and September. During this time, Lavender is also susceptible to a soil fungus that splashes up onto the lower portion of the plant, slowly killing the foliage from the bottom up. Mulching deters this process from happening; planting Lavender in containers will also help in preventing the soil from staying too wet. It is good to understand that in our Florida climate, Lavender simply gets an “attitude” dealing with these harsh summer conditions, but it’s not impossible to grow knowing this.
Q: Can I grow herbs inside?
Yes, but it takes some attention to their needs. Herbs need plenty of sunlight to grow well, and the inside of a house usually does not provide enough of it. A sunny window that gets at least 4 hours of sunlight might do the trick. Also, as herbs grow outside, there is an interaction with the air that is the basis of their growth, which does not take place inside the home. As a result, herbs need much less water when grown inside the house than outside. So, it is wise to monitor closely the water needs of your herbs and be careful not to overwater. If you find your herbs stretching and getting “leggy,” it is a sign there is not enough sunlight, and you may need to find a brighter location.
Q: Why do my herbs die?
A basic lack of understanding of the basics of herb growing generally leads to herbs dying. Two of the most common reasons that herbs die are not enough sunlight and too much water. Certainly, there may be other causes, but these are quite common. Also, many times it is the result of some cultivation process like pruning during the wrong time of year that leads to an herb’s death. For example, Lavender and Rosemary are two hot-weather herbs with thin, oily leaves. Thus, the transpiration rate is very slow. During the rainy months, these herbs need all the help they can get to get rid of soil moisture. Often gardeners will prune these two plants during the rainy summer months hoping to encourage new growth, when in fact, they are removing valuable leaves that will help get rid of the moisture in the plant. The result usually is a quick end to the herbs.
Q: Herbs like to be neglected, is this true?
I am not familiar with anything living that likes to be neglected. It is a common thought among many new gardeners that herbs like to be neglected because they see them growing and thriving in many dry areas around the world. Herbs, like other plants, thrive on sunlight, rich soil, some fertilizer, and a bit of water now and then. These together provide the ideal conditions for healthy growth. When they are lacking in any of them, the plants will certainly survive, but I would imagine they would display some deficiency symptoms. If you make an error when growing herbs, they will amaze you with their ability to survive neglect and recover, but neglect is something I wouldn’t suggest they actually like. A point of interest to make on this subject is that herbs that do survive the rocky, dry areas in many locations throughout the world have been ‘naturalized’ over a very long time and are able to survive these conditions. Planting an herb in a dry, sandy, rocky area, and neglecting it will not produce a happy herb.
Q: Is it too hot to grow herbs?
No and yes. Our hot temperatures help induce the production of oils and give us herbs with more intense flavor, aroma, and color. But, our hot and humid summers can make it difficult for some herbs to thrive.
Those hot temperatures are the result of a very strong sunlight source and it is the sunlight intensity that often gets confused with temperature. Sunlight hitting on sandy soil can cause the soil temperature to rise well above 100° often damaging many of the shallow roots herbs produce. These damaged roots can no longer absorb moisture and thus the herbs wilt and may eventually die. Also, our light intensity is so strong in the summer that it may bleach the chlorophyll in many herbs like Parsley.
This is why it is important to choose herbs that are well adapted to your climate and soil. Herbs that are native to your region or to regions with similar climates will typically perform the best. Also, planting herbs in raised beds or containers can help improve soil drainage and provide better growing conditions. Proper watering, mulching, and adequate fertilization are also essential for successful herb growing in hot climates.
Q: When is the best time to Plant?
The best time to plant herbs is right now! While I plant herbs all year long, there is an advantage to planting them in the Fall. Why? Fall provides ideal weather conditions for herbs such as low humidity, very little rain, bright sunlight, cool nights, and warm or even hot days. Most herbs will grow well under these conditions. Since many herbs are also very tolerant of cold weather in North Central Florida, they continue to grow throughout the Winter, although slower due to lower light intensity. During the Winter months, while the tops grow slowly, the roots spread throughout the warmer soil. As a result, when Spring arrives, and the hot Summer months follow, your herbs will have developed a deeper root system and be better able to handle the hot soil temperatures.
Q: My thyme dies, what am I doing wrong?
Thyme has very small leaves, resulting in slow transpiration. It can become very dense, creating a perfect environment for humidity and moisture to develop around the leaves, often leading to fungus problems. Try growing thyme in window boxes or baskets to give the leaves an airy condition and allow for more control over soil moisture by watering less. Every now and then, give your thyme a good haircut within 1″ of the soil to invigorate the herb and produce fresh new growth. However, when you prune this low, you are removing leaves that allow water to leave the plant, so the herb will require only the slightest amount of water until new leaves appear. “Prune the leaves ~ Prune the water.”
Q: Why does my Cilantro always die?
Cilantro is actually coriander, a warm-weather herb that produces wonderfully scented coriander seeds. This seed production is energy-intensive and often occurs at the expense of producing many leaves. Warm night temperatures trigger seed production. In order to have an abundance of leaves instead of seeds, the coriander plant needs to be grown in the cooler months when night temperatures remain in the 50°-60° range or lower. Sparse growth of coriander during the warmer months often leads gardeners to think the plant is not doing well and dying. It may also be due to too much watering.
Q: How often should I water my herbs?
As a rule of thumb, I let the herbs signal to me when it is time to water by their slight wilting. This may occur once a day or every few days, depending on soil conditions and weather. Windy days increase transpiration and wilting, while cold cloudy days minimize transpiration, and the soil stays wet much longer.
Q: Why does my rosemary get black spots and loose leaves?
This is a sign of a fungus caused by too much humidity or moisture around the herb. Make sure your soil is well-drained and avoid watering with overhead sprinklers or wands. Water close to the plant base if necessary. Clean away older dead leaves that may be infected, and do not prune the herb if this occurs during the rainy months of July – September, as this will cause extra stress to the plant already dealing with too much moisture.
Q: Why does my Basil get black spots?
This is a common problem on basils in high moisture areas due to too much water, insufficient soil drainage, and poor air circulation. Some basil varieties are also prone to getting leaf fungus or black spot. Ensure your basil is grown in-season and has adequate air circulation. Try to water the herb so there is enough time in the day to dry before it gets dark. Remove all infected leaves.
Q: Why does my lavender drop leaves and die?
Lavender is susceptible to Septoria leaf spots, often caused by fungus spores splashing up from the soil during the rainy season. As the lower leaves become infected, they eventually drop off and weaken the plant. In severe cases, this will spread all the way up the plant. Mulching with builders’ sand is very effective in minimizing this fungus as it creates a barrier with no organic matter to hold moisture, and the water passes through the sand with minimal effect on the plant. The cause, however, can be too much watering, too much rain, wet soil, and a lack of air circulation.