Herb Gardening FAQ

Growing Herbs in Florida

Over the past 20 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. I will answer these questions here and as new ones arise I will include them here as well.

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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?

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    •      Q: What are the easiest herbs to grow?
    •    Growing all herbs is easy, if you understand what conditions they like. If you do not know much about herbs or their growing requirements I’d have to say the following herbs, are some of the easiest to grow….Parsleys, Oreganos, Chives, Tarragon and Mints.
 Certainly there are many more and it is a matter of gardening knowledge, but I would have to say these are pretty easy. 
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?
    •    My first response to this question is “What are you fertilizing the herb with?”  Often, the response is nothing, thinking the natural fertilizers in the soil are enough ( ie leaves, organic matter, etc. ). While in many occasions this may be true. But it takes a very rich, well balanced soil to be the only source of food for a plant. Here in Florida, we have soils from very sandy to those with a large amount of clay, both lacking in natural organic matter and nutrition. The result is an herb that not only shows very little growth, but one that will also develop deficiency symptoms. Know your soil type and if your soil is poor, you will need to apply a slow release, organic fertilizer. Feeding the plant however, is not the only solution, and you should consider building your soil up with compost so in the end you are feeding your soil and the soil will feed your plants.

           •      Q: Is it true you can’t grow lavender in Florida?
    •    Not true at all! The key to growing Lavender is understanding the conditions Lavender grows best in….hot, plenty of sunlight, low humidity and well drained soil. Lavender also prefers, as many herbs do, an alkaline soil.
Because Lavender is high in essential oils, the 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. Lavender, during this time, 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 is usually not the place to provide 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  and that interaction does not take place inside the home. The result is, that herbs need much less water, growing inside the house than outside and so it is wise to monitor closely the water needs of your herbs and be careful not to over water.
If you find your herbs stretching and getting “leggy” it is a sign there isn’t enough sunlight and you may need to find a brighter location.

           •      Q: Why do my herbs die?
    •    A basic lack of understanding 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, a rich soil, some fertilizer and a bit of water know and then. These together provide the ideal conditions for healthy growth and 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 in 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 survuve 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 the flavors we want from our herbs. Of course 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.

           •      Q: When is the best time to Plant?
    •    The best time to plant herbs is right now! I plant herbs all year long, however there is an advantage to planting them in the Fall. Why? Fall presents us with the ideal weather that herbs like: low humidity, very little rain, bright sunlight, cool nights and warm, even hot days. You will find most herbs will grow under these conditions very well. Since a majority of the herbs are also very tolerant of cold weather here in North Central Florida, they continue their growth throughout the Winter ( although slower due to the lower light intensity ). During these winter months while the tops grow slowly, the roots are spreading throughout the warmer soil. As a result, when spring arrives and the hot summer months, your herbs will have developed a deeper root system, better able to handle the hot soil temperatures in store for them.

           •      Q: My thyme dies, what am I doing wrong?
    •    Thyme has very small leaves. As a result transpiration is slow. Thyme can get very dense and with the leaves so close to the ground, the perfect environment is created for humidity and moisture to develop around the leaves, often leading to fungus problems.
Try growing thyme in window boxes or baskets. This gives many of the leaves an airy condition as well as giving you more control over the soil moisture by watering less. Every now and then, give your Thyme a good haircut, within 1″ of the soil; this will invigorate the herb and produce fresh new growth. Do not forget however, when you prune this low you are removing leaves that allow water to leave the plant. Since the leaves are gone, the herb will require only the slightest amount of water until new leaves begin appearing. “Prune the leaves ~ Prune the water”.

           •      Q: Why does my Cilantro always die?
    •    Cilantro is actually Coriander. Coriander is a warm weather herb that produces the wonderfully scented Coriander seeds. This process of producing seeds is energy intensive and often is at the expense of producing many leaves. This seed production is triggered by warm night temperatures.
The problem, if we can call it a problem, is that we have come to love the great flavor of the leaves! The leaves have been given the common name Cilantro. In order to have an abundance of leaves rather than seeds, the Coriander plant needs to be grown in the cooler months when the night temperatures remain in the 50°-60° range or lower.
Often the sparse growth of Coriander during the warmer months signals to many gardeners expecting the Cilantro leaves that the plant is not doing well and dying. It may also be 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 be once a day or once every few days, depending on your soil conditions and the 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 watering is necessary. Clean away older dead leaves that may be infected and do not prune the herb if this is 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 that are in a high moisture area, due to too much water, not enough soil drainage and poor air circulation. Some varieties of Basils are also prone to get leaf fungus or black spot as it is called.
Make sure your Basil is grown in season, has adequate air circulation and 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 spot, 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 to the plant. The cause however, can be from too much watering, too much rain, and wet soil and a lack of air circulation.



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