Basil Problems

The first comment that I had with my blog was from someone asking for me to continue writing about what
Poorly maintained basil
to do when one encounters a problem with growing basil. Unfortunately, I don't know who that person is as the comment was made anonymously. I wish the reader left some information so that I could email him or her personally back then. I was so busy with my writing jobs that I had no time to update this blog.
So now, better late than never, I am writing about how solve common problems with growing basil in containers and how to go around them.

Poor Watering

The first problem is, of course, watering. If you are to compare this picture from the basil photos that I had when I was just starting with gardening, this one is obviously poorly maintained. Watering here is an issue since the leaves at the bottom have already grown yellow. Aside from that, the leaves are crinkly, they are curling upwards and have a tough texture. This basil plant is not under my care, sad to say. This is my in-law's basil plant which is being tended for by our helper. Since the poor girl has time management issues as well as poor water supply location, she waters the plants in the garden in a poor pattern: too little, too much, enough, too little, too little, and so on. Even if you put on leaves for mulch, you will still have a problem with watering your basil if you do it everyday.

Solution: Deep watering

Deep watering is the best way to provide moisture to basil plants, may it be you're from a tropical climate, the US, or from paradise. Seriously. Even if you have the perfect weather conditions, the perfect location for growing basil in containers, or even the perfect tomato as a companion (yeah, someday, we'll do duo-planting), if you do not observe the soil's water content, you are bound to have problems later on. For those who are just beginning, the best way to water basil is to give it water until you see it overflowing from that small hole at the bottom of your pot. (You do have a hole at the bottom, don't you??) This is to be done every 3-5 days, depending on how hot weather conditions are. If you are not sure, then observe the soil daily. Touch the soil and feel it. Take note of the texture and the density.
  • Dry soil is coarse, loose, and light in weight and color
  • Moist soil is smooth, crumbles to the touch, and relatively smooth and deep in color.
  • Wet soil is slippery, sticks together, and just feels plain wet and dark in color.
What you need is to maintain a smooth, moist soil up to 2 inches below the top soil. Poke your finger in the soil and check the moisture. If it's moist up to 2 inches, then no need to water the pot. If you are not sure, get a pencil or a thick bamboo skewer (barbeque stick). Do not water if you see moisture on the stick. If the stick comes out dry, then it's time to deep water the plant.
Don't worry about deep watering. As long as there's a hole at the bottom of the pot as well as broken terracotta pieces or pebbles at the base, drainage will not be an issue.

Downy Mildew

Aside from poor watering, this plant is also suffering from the dreaded downy mildew. It is caused by the Peronospora belbahrii which is spread through contaminated seeds and through wind. High humidity and high moisture exposure are also culprits for the infection.

The leaves will show signs and symptoms of poor nutrition, which will spur on an eager home gardener to shower the basil plant with tons of fertilizers which will just make things worse for the plant. To differentiate, look beneath the leaves, particularly those that are discolored and sickly looking.

You may tend to disregard this dust-like presence as dirt. Naturally, you would want to clean up your basil leaves by drizzling water over them during your average garden routine. However, adding water to leaves will just aggravate your basil's sorry condition. Microorganisms thrive in water, so moisture on the leaves will just promote the growth of the
spores and not wash them away.

One can never be too sure if this basil plant came from infected seeds. What I do know is that most casual gardeners tend to water their plants right on top of the leaves, thinking that the extra moisture on the plants will be beneficial. Quite the contrary, doing so on any plant especially when weather conditions promote poor evaporation (i.e. cold temperatures, high humidity), mildew can and will still form. I've had cuttings from the very same healthy plant that developed mild dew on a very early stage because it was constantly immersed in water during root development.

The helper's poor care and bad watering practice created a strain on this basil plant. As a result, the resistance of what could have been a perfect basil plant, the microorganism that may have been dormant (or already present in the air, we do not know) in the plant developed and harmed this basil.

Solution 1: Removal
The sad part is that there is no known way yet to cure and treat downy mildew. That being said, if the infestation of the powdery mildew is as strong as this one, the only option is to remove the plant and discard the soil. The good thing about container gardening is that you do not have to be concerned about a large plot of land getting infected with mildew. Do not worry about the waste. If you insist on letting the basil grow, you will get a wretched plant giving you leaves that are just not up to the taste. Just discard the leaves that have been infested and store the relatively healthy ones by chopping them up and storing them in ice cubes for future use. If you keep that basil and decided to buy another set of seedlings, you will just be spreading the spores to the new ones. Yes, the spores are easily spread through the air, so please be merciful to the basil population and discard your sick basil.

Solution 2: Improve Watering Techniques

Water directly at the soil instead of the foliage. This way, you lessen the amount of moisture on the leaves and leave it where your basil needs it most: at the roots. If you can afford it, consider installing a ground irrigation system that is designed specifically for container gardening or raised bed gardening. If you are using a ladle or a garden pail, resist the urge to shower your basil with water on the leaves. Just direct the spout or the lip around the soil, and you're all good.

Solution 3: Improve Air Circulation

Humidity will be a problem, especially during summer time. Stagnant air will further promote spore development, causing the spread of microorganisms in your plants. It is best that you place your basil plants at least 3 feet apart for good air circulation. Keep them away from other plants that are sick so that they will remain healthy. If your basil is already sick, separate them from the healthy ones and discard the entire plant properly so that the spores will not spread Solutions 2 and 3 are not exactly solutions, but more like preventive measures to ensure that your basil will have a good chance against mildew.

Root Rot/Damping off

Your basil will suddenly wilt for no reason, before finally collapsing. It's caused by Rhizoctonia solani, a microorganism that thrives in high humidity and poorly ventilated areas.

Solution: Sterile Pots and Good Ventilation

The best way to avoid root rot is to transplant your basil on really clean containers. Scrub the pot well with soap and water to take out most of the dirt grime. Leave hard, stuck up deposits for later. After rinsing, you have to soak the pots in a sterilizing solution. Your solution could be:
  • Bleach: mix 1 part bleach to 9 parts of water (i.e. 1 liter of bleach to 9 liters of water).
  • Vinegar: 1 part vinegar to 1 part water (i.e. 1 liter of vinegar to 1 liter of water).
Make sure that the pot is fully submerged in the solution for 30 minutes. If not, you should rotate the pot every 30 minutes until the entire pot is sterilized. Once the soaking time is done, get a steel brush or knife to scrape off any mineral deposits that you were not able to get rid off earlier. Rinse your pot with lukewarm water thoroughly, wipe off any excess water, then let it air dry. As with ventilation, make sure that the area has good air circulation and space plants at least 3 feet apart.


Photo: Wikipedia
These pesky, green, semi-transparent bugs suck out the sap of your basil to produce honeydew. Ants may love 'em, but gardeners hate them because aphids are just like leeches who suck out nutrients from your plants. You can often see them as slimy, somewhat yellowish patches located at the underside of the leaves where the aphids often congregate for a feast.

Solution 1: Hose Them Off

They may stick to the underside of your basil, but they can be easily removed by blasting them away with your garden hose once you see a couple to prevent them from spreading. They multiply like rabbits, so prompt action is needed.

Solution 2: Garlic spray

I am not a fan of using chemical insecticides, particularly on herbs that you will definitely cook and eat.  Here's what I can suggest: make your own garlic spray. You will need
  • 3-4 cloves of garlic, finely chopped
  • 2 teaspoons mineral oil
  • Strainer or cheese cloth
  • Sprayer
  • Dishwashing soap
  • Water
Mix all the garlic an oil together and put in an air tight container. Store in a cool, dark place for 24 hours so that the oil will absorb all that potent garlic aroma and chemicals. Strain the garlic from the oil using a fine mesh strainer or cheese cloth and add the oil to half a liter or a pint of water and 1 teaspoon of dishwashing soap. This will be your garlic oil solution. To use,  get a sprayer with half a liter of water and add in 2 tablespoons of the solution, then shake well. Test the spray first on a small part of your basil and see how it takes the spray. Let it stand and come back to that same spot after 24-48 hours. If you don't see any damage, your spray is safe to use. Do not use any other oil aside from mineral oil. I made an experiment and used olive oil for my garlic spray. Result: ants made a feast of my plant. Not a good sight, and no amount of watering could take the ants off my basil. Note: garlic spray can also kill beneficial insects in your garden. Use cautiously. 


These insects are tiny, green, and have a distinct wedge like appearance.  You can see them at the underside of the leaves, and they leave black patches or multiple yellow spattering discolorations on the leaves. The leaves also become dull, brittle, and rough to the touch.  Aside from harming the plants and causing cosmetic damage, the leafhopper can also spread diseases between crops.

Solution 1: Hose Them Off, Too

They sticky, but very light. Blast them off with your garden hose once you find these insects on your basil

Solution 2: Insecticidal Soap

Your local organic garden store has a variety of sprays that can help you eliminate leafhoppers. Ask for a good insecticidal soap and read carefully on the label how to use it because these solutions are very potent. Insecticidal soaps are different from dishwashing soaps  because the former contains amino acids that can penetrate the hard, outer shell of insects and cause them harm. Be careful in using insecticidal soaps as it can also kill other beneficial insects in your garden. There you have it, the most common problems gardeners face when taking care of basil in container gardening. Do you have a problem growing yours? Why not share them with us so that others can also talk about their tried and tested solutions? Hope you will leave a comment and share your experience, I would dearly love to hear from you. See you around.