In the world of gardening, there are many things which can go wrong. A sudden frost can wipe out your entire crop, an assault of pests can leave only half-eaten plants behind.
It is true that some things cannot be avoided, but still, the consequences can be softened by dealing with the problem. Because of that, here are 25 common basil problems and how to fix them; I hope that you won’t need this text too much.
Table of Contents
- Required Tools
- Physical Causes
- Under-Watered Plants
- Overwatered Plant
- Nutrients Shortage
- Stunted Growth, The Plant Is Small, With Smaller Leaves
- Limp Stems And/Or Black Leaves
- Small Leaves And Flavor Is Weak
- White Leaves (Or Pale Spots On Leaves)
- Margins Of Leaves Are Brown; Leaves Fall Off
- Leaf Margins Turn Brown, White Crust Forms On The Top Layer Of The Soil
- Small Leaves And Old Ones Fall Off (Only For Container Grown Basil)
- Problems Caused By Microorganisms
- Problems Caused By Pests
Luckily, not all methods listed here will require heavy lifting. Some of them include just a different approach to what you have been doing already. Others will need your creativity. Just in case, keep standard gardening tools close at hand. The bucket might be handy, different types of fertilizers, spade, and of course, a soil test kit.
The latter is beneficial when it comes to applying fertilizer since you can check how much nutrients there are in the soil before start feeding. You can also consider using a pH test kit. These are often rich with other information, such as temperature and the amount of light in this area.
As for other tools, I will list them in every chapter separately. Speaking of sections, I will divide problems into groups, according to their cause. This way, you will (I hope) find your way through the article much faster. Of course, these reasons for basil not progressing well are the most common. Because of that, groups will be uneven.
This group is made of problems which are caused by negligence, insufficient knowledge or bad overall conditions which may include, for example, rain when it is not wanted. Not all of them can be averted, of course, but the majority can be corrected.
Appearance and causes – although basil is considered as overall easy to maintain, its watering rhythm can be tricky, especially during summer, when the land dries out much faster. If you notice that plant has hanged its leaves and that they are soft and the leaves are limp, it probably needs water.
Solution – basil will require moderately watered soil to progress. This is achieved by watering with smaller quantities of water, but more often. Of course, during summer, watering in the morning is the best.
Appearance and causes – at first sight, basil looks the same as when it is without water. Usually, you can look at the ground and see if it is damp or not. But, in the summer, the top layer of soil might be dried and look cracked, but underneath there might be still more water than it is needed.
Solution – take pH testing kit I have mentioned earlier. Many of those can measure the humidity in the soil. If lower sections of the ground are wet, distribute the same amount of water to be dispersed more often.
Appearance and causes – since basil is grown primarily because of its leaves, the most crucial nutrient for this plant is nitrogen. If you notice that leaves are wilted, the growth is stunted, or overall look of the plant is not satisfying; you could doubt that lack of nitrogen is causing this.
Solution – you can either make fertilizer or buy it, it doesn’t matter, as long as it is high in nitrogen. Feed your plants once, and see if something has changed. If it begins to look better, this means that you guessed what the problem is, so continue with applying fertilizer, but don’t overdo it.
Appearance and causes – in case you noticed that your precious basil is looking a bit “burned” with a yellowish tint, check on how much fertilizer you have added. Again, soil test kit is your best friend, and if levels of nutrients are high, it is likely that the plants are suffering from burns made by fertilizer.
Solution – in general, there is not much you can do. You can’t remove nutrients from the soil, and if you try to dilute it with water, you may overwater the plant. The only solution is to sit and wait for it to dissolve.
Stunted Growth, The Plant Is Small, With Smaller Leaves
Appearance and causes – in case that sudden frost has surprised you in spring, it is possible that basil will survive, but this will leave consequences. Stunted growth is the most apparent sign that the plant has suffered some frost shock.
Solution – basil shouldn’t be planted before the temperature of the soil settles at 60 degrees Fahrenheit. In case that you planted it, and the weather is still cold, try applying soil covers, since these can lift the temperature by few degrees.
Limp Stems And/Or Black Leaves
Appearance and causes – as the title says, if you see some leaves turning black, you might have a problem with frost (again). However, this happens when the temperature drops below 50 degrees.
Solution – if you have this situation at hand, use row covers or those made of plastic until the cold weather passes. This is also a useful solution for sudden spring frosts. Those leaves which are black should be cut off, to prevent the whole plant to weaken.
Small Leaves And Flavor Is Weak
Appearance and causes – although the soil where basil is planted can be rich in organic matter, it might still miss essential nutrients. If the taste of basil is diluted or weaker, it probably needs fertilizer.
Solution – use 5:5:5 fertilizer in the form of granules. You can apply it twice a month. This is important when you begin to harvest leaves because this is the time when the plant needs all the nutrients it can get.
White Leaves (Or Pale Spots On Leaves)
Appearance and causes – this problem is caused by too much light. Although basil loves sunlight and can endure whole 12 hours of it, sometimes some leaves or plants might be more sensitive. Leaves begin to pale with white spots on them.
Solution – if you are growing basil in containers, move them somewhere with less light. On the other hand, if you are growing them outdoors, row covers are great to solve this situation. They create partial shade and will keep pests away. Also, cut off any affected leaves.
Margins Of Leaves Are Brown; Leaves Fall Off
Appearance and causes – too much heat can cause a bit of a problem for basil. In case that you are watering your plants as it should, and some of the leaves are browning on the edges with stems growing too tall, it is possible that the temperature is too high.
Solution – although we cannot influence the temperature of the Sun, there are few things which can be done to reduce damage. First of all, add mulch around the plants. This is an excellent method for both keeping the moist in the ground, as it is for cooling down the soil. And it will also make things difficult for weeds to develop. In cases of extremely high temperatures, add row covers.
Leaf Margins Turn Brown, White Crust Forms On The Top Layer Of The Soil
Appearance and causes – this white layer on top of the ground is the first sign that the water you are using to water basil is not entirely suitable for this purpose. It is probably alkaline, and because of that, this happens.
Solution – you will have to separate one barrel and fill it with water and leave it for a day to settle. Use it to water basil plants. Also, misting might be handy, and there are oscillating sprinklers which can help you in this matter. Of course, do not overdo it with fogging, since water is already alkaline.
Small Leaves And Old Ones Fall Off (Only For Container Grown Basil)
Appearance and causes – in case that you notice wilting of the plant despite proper watering, and that new leaves which grow are a lot smaller, it is highly likely that your basil will need a new and bigger pot or container. Also, if you see roots peeking through the watering holes, this is an absolute sign of this problem.
Solution – repotting will be to solve this situation. New pot should be more prominent, and you should remove any old soil from roots, because that is already spent of its nutrients, and can stop roots from properly developing.
Problems Caused By Microorganisms
As I said, basil is not overly fond of too much water. If the soil is continuously soaked, it can lead to several types of fungal diseases. In any case, some of them can be treated, but for some the only way to stop them is prevention.
Yellow Leaves And/Or Orange Blotches
Appearance and causes – if you notice that the basil is struggling, with yellow parts appearing and even orange spots on stem and leaves, it is highly likely that Fusarium Wilt is responsible for this condition. This disease is persistent and can lead to severe damage to harvest.
Solution – unfortunately, there is no cure for this disease. You have to remove plants which are affected, and not to use the same spot for planting basil in the next five years. In the future, avoid wetting foliage during watering.
Brown Or Black Parts Of The Plants
Appearance and causes – in case that your basil has some blackish or brown areas along leaves or stems, it is possible that the plant is suffering from Pseudomonas cichorii bacteria. It is spread by infected soil splashing on the plant.
Solution – this disease also can’t be cured, but prevention and stopping it from spreading might be done. Start by removing infected leaves and plants, and try to be careful when watering basil, so that no soil is transferred to plants. A word of advice is to cut the leaves when the foliage is dry so that it won’t spread further.
Mold Develops On The Underside Of Leaves
Appearance and causes – this disease wasn’t affecting basil until a few years back. Downy Mildew is caused by a fungus, and too much moisture in the air accelerates its spreading. Also, it is spread by the wind so that it can kill a lot of plants very quickly. It is recognized by a mold which appears on the underside of leaves.
Solution – this disease can’t be cured, and all you can do is to remove infected plants. As with similar fungi, you will have to avoid planting basil at the same spot for the next four years.
Leaves Are Yellowing, And Roots Are Squishy To Touch
Appearance and causes – perhaps the most famous disease which appears on basil, damping off or root rot is caused by fungus. If you doubt this disease, pull one plant from the ground, if the roots are in bad shape and soft, this means that it is affected. The fungus clogs the main lines of supply, and the plant slowly dies.
Solution – there is no “cure” for this disease, but you can perhaps save the plant. First, remove it from soil and wash the roots. Cut off any infected parts and plant it again in a different spot. With some luck, it will get through. Also, watering should be careful and moderate.
Gray Growth On Stems And Leaves
Appearance and causes – if you spot any grayish spots on your basil plants, it is highly likely that it is suffering from the gray mold. It is a fungal disease and is caused by too much water or plants sown too thick.
Solution – the best way to avoid this to happen is to give plants the space they need. Make sure that you are planting them with at least 1 ½ feet of space between seedlings. Also, do not overdo with watering, and if it is possible, utilize a dripping system which is far the best for basil.
Problems Caused By Pests
Luckily, there are not many pests which will feed on basil. Still, if they are left unattended, they can cause damage, stunt the growth of the plant and be an overall nuisance.
Appearance and causes – aphids are most likely to attack young basil plants since older ones are resistant enough to survive without much trouble. They feed on foliage and can be seen by naked eye, but the most apparent sign of these pests is sticky goo found underneath the leaves.
Solution – the easiest way to keep aphids away is to remove them by hand. This is the most natural way to do so, and in cases of more massive infestation, you can use ladybugs as the matter of control.
Appearance and causes – although they will rarely attack basil, spider mites might decide that having this plant for supper is a good idea. They are sucking the juices out of leaves and stems and can cause some damage. Trademark of these bugs is the webbing they leave behind.
Solution – neem oil diluted in water and a drop of garden soap is what you can use to fight these little rascals. If you wish to utilize all-natural solution, ladybugs will be more than happy to lend you a hand.
Appearance and causes – these small insects can be seen by naked eye, and will often feast on basil. They feed on foliage and can cause severe damage if left unattended. The result of their work looks like a scar on the leaves.
Solution – since thrips have a preference toward weeds, removing any of these as soon as they appear will reduce their numbers. Also, rotating crops is vital and can help you on this matter.
Appearance and causes – even if they are slow, slugs will eat their way through basil rather fast. They eat the leaf in whole, not just foliage, and can be easily spotted.
Solution – some people are recommending to use salt to kill slugs instantly, but I cant make myself to torture them. My preference is to put a plank on the ground between lines of basil and wait a couple of days. Slugs will gather on the lower section since they are looking for shade to sleep so that I could transfer them out of the garden.
Appearance and causes – as if snails are not enough, we also have nematodes which can attack basil. Besides eating through the root system, they are releasing toxins which are slowly killing the plant. If you notice wilting, check the roots, the apparent sign of those pests are deformed root system and lumps created on them.
Solution – fish emulsion is known method for countering damage made by the toxins of these pests. Try applying this, and rotate crops regularly, since their eggs are left in the ground.
Appearance and causes – as the name suggests, these pests are white, and they fly (of course). They will feed on plant’s juices which will make it weak. Although basil can deal with this situation, why not helping it? If you shake the plant and the cloud of white insects arises, those are whiteflies.
Solution – insecticidal soap is the most efficient way of dealing with these pests and can be bought almost everywhere. Just cover all the leaves, since they can reproduce rather fast.
Appearance and causes – imagine beetles which are jumping as fleas. Those are pests which can feast on basil, and you will recognize them by this feature.
Solution – row covers are great for keeping them at bay since they can’t attach to leaves which are protected. Also, Diatomaceous Earth is good for tackling severe infestation.
Appearance and causes – most of these pests will invade in swarms, but not this one. The Japanese beetle is recognized by the metallic color of its wings, white stripes on sides and the fact that they are attacking in groups. They eat green parts of leaves, with only veins left behind.
Solution – either remove them by hand or plant geraniums. They will be attracted by this flower, eat it, get dizzy, which makes the collecting job much more manageable. Also, utilize row covers in June, when they feed the most.
Appearance and causes – some bugs have taken the defense to a higher level. Scales (some varieties) will create an outer shell on the stem of the plant, where they will live their happy lives by sucking the juices out of the plant. They can be seen easily, but can also be considered as a non-living entity.
Solution – lacewings, and ladybugs are most effective in eradicating these pests, and since I don’t like the idea of using insecticide since it can kill already jeopardized bees, I recommend either this or any form of essential oil. This is also a great way to remove them quickly and efficiently.
Here they are. All of the 25 common basil problems and how to fix them are listed above, and I hope that you won’t be needing this article too much.