Basil Pests and Prblems

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 Updated 12/05/2017

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Basil is generally pretty easy to grow, so you shouldn't encounter too many problems along the way. However, there are a few issues that can arise which may affect the health of the plant, so if you think your plant is looking a little poorly, have a look at the questions and answers below to see if they can help.

Holes in my basil leaves!

Help! Scouring the web to see if I can get any advice on how to get rid of whatever it is that is eating holes in my basil leaves. I plant in NYC in a backyard. Would dearly love some suggestions.


Hi, I've got to say that I have never grown basil outside without huge pest problems. If it is not slugs that are damaging your basil then I suggest using cloches of some kind to create a physical barrier against the pests - these could be horticultural fleece, or plastic or glass. Keep the plants well watered if they are cloched of course.

I suggest making sure that you are not just suffering from slug attacks, if you are then try picking them off, failing that you might try nematodes - a biological control - to create a slug free zone around your plants, these should be available through good organic gardening catalogues.

Finally I would propose that you grow your basil under cover from now on. You still have time for a last sowing this year, and of course this in itself is a good response to pests: sow every fortnight throughout the growing season, and you'll keep your supply of basil going whatever the pests do.

Unwelcome bugs

I planted basil plants five days ago in my front garden, and they are going great, except that this morning I noticed that the leaves have been bug eaten in spots on most of the plants. Do you know of any bugs that would be eating my basil? And do you know of a natural, non-chemical way to control this?


Slugs love basil, they would be my prime suspect. There are a number of anti-slug measures you could take. You could try grit at the bases of the plants; soil level beer traps; bran around the base of the plants; copper taping around the plant pot etc. Probably the most effective in the long term would be to improve the bio-diversity of your garden: try a pond to attract frogs; frogs eat slugs.

It may sound a little silly, but go out after dark with a torch and try to catch the culprit in the act. If there are slugs then picking them off is a quick way to even up the odds for your basil plants. If we are not talking slugs then pests can still be picked off and disposed of; in the meantime you will have identified your pest.

There are few growers that I know who are lucky enough to be able to grow basil outside without major pest problems. In the long run it might be that you need to grow basil under protection and use the space outside for something less attractive to slugs.

Basil wilting

I planted some basil seeds indoors about a month ago. We have been keeping them well watered and in direct sunlight as much as possible. They have grown to be about an inch tall. Yesterday, we set the pots outside in the sun and all the plants wilted and now look as if they are going to die.
What have we done wrong?


Okay, it sounds as if you were doing fine up to a point. I don't know what the weather was like when you put them outside, but two things might have happened: firstly it might have been too much of a sudden change in temperature for the little plants, or secondly, and I think more likely, they suffered from sudden exposure to drying conditions, perhaps a breeze and the sun left them dry enough to wilt.

If the seedlings had relatively shallow roots then drying of the soil surface might have been enough for a dramatic effect. They might be salvageable if you take them in and water them well, but the bad news is that basil doesn't like to suffer a check like this, and even if it lives it might decide to flower prematurely as soon as it can. In any event, and whatever caused the failure, basil can be sown successionally right through to the end of summer, so don't despair, get some more seeds in compost and keep it warm and watered inside until it is 120mm tall at least before risking it outside.

The most important factor in growing basil successfully is to keep it watered correctly - keep the growing medium moist, but not sodden. Good luck with your basil, it is well worth persevering.

Basil yellowing

My basil plants seem strong but I have noticed that the leaves are looking yellow. I water them a couple of times a week and they get about 6 hours of sunlight a day. Any help?


Basil is an annual and will only last one season. The plants will flower, seed and die. The yellowing you are seeing could just be ageing. Sometimes it can help if you stand basil in a tray of water (but the plants tend to put out masses of roots).

It is a good idea to nip out any flower buds as soon as you notice them to prolong the life of the plant. If you are growing basil for use it is best to grow it by sowing every two weeks during the growing season and using it as soon as it gets big enough.

Trimming basil

What is the best way to harvest or trim Basil?


The best way with sweet basil if you want to use it is to simply make a sowing of it every 2 weeks and then just rip up the plants and use the leaves etc as soon as you can. If however you want to have several plants to keep growing for as long as possible you can harvest no more than one third of the leaves at one time. You need to nip out any flower buds to extend the life of the plant but as the plant gets older this becomes increasingly difficult and the plant will eventually die.

Replanting basil

Can I replant any of my basil plants? I planted six plants and they really took off. They are right next to my tomato plants - and I am needing room - I had no idea the basil would get this big. Thanks


I have replanted basil successfully but when it was quite small. I guess that the most important thing would be to dig up the max possible of the roots and then water it in really well in its new home.Dig a nice big hole for it and add plenty of water.Not infallible but might work!

Keeping picked basil fresh

It seems that whenever I pick my basil it seems to wilt or get soft within a few hours or a day. How do I store it or what do I do so this does not happen?


Basil does wilt v.quickly. It may help if you put it in a pot of water (like a bunch of flowers) and put it in the fridge (this is how mint used to be kept fresh in greengrocers and watercress for that matter tho not in a fridge)

I have had some success freezing basil leaves in plastic bags but sometimes they go black.Chopped basil can be frozen in ice cubes for later cooking use.

Drying basil

When I tried to dry my basil ,all of the leaves turned black. I have successfully dried peppermint with no problem using the same method. I hang them from a rack in my kitchen. What have I done wrong?


For very clear instructions on how to dry basil, try Methods of Drying Basil (external site).

Basically, basil should be dried quickly in the oven or in one of those electric vegetable and herb dryers.

Basil turning black

Help ...The tips of my basil leaves are turning black....mostly on the Thai basil....any suggestions?


Basil leaves do turn black eventually, especially when the plants are pot grown. The point about basil is that it is an annual and therefore will not last for more than a season.

Freezing basil

Can I freeze or keep refrigerated for a while, my lovely basil leaves that I am growing in a pot outside? I hate to see them wasted!


I have frozen basil leaves with some success. I literally put the leaves into plastic bags and froze them. They darken in colour but are usable. Drying is probably a better option for basil or make the leaves into loads of pesto!

Basil losing colour

I potted basil purchased as a small plant about a month ago. The leaves have lost their dark green color and are now light green to yellow. I have them in good sun and keep the soil moist. What is the problem? Can I fertilize with anything to help the color and leaf size?


Basil is an annual and will not last for ever in a pot. You can pinch out the flower buds to prevent flowering to prolong the life of the plant or you can try standing the pot in water to improve the colour. Ultimately the plant will die because it is an annual. a solution is to sow basil seeds every 2 weeks during the growing season and use or freeze the leaves as they mature.

Propagation by cuttings

My basils were initially started from seeds. Just recently, I experimented with propagating by cuttings, sticking pruned stems into rich potting medium. The stems took root and are now flourishing. My questions is - are those basils from cut stems new plants, or are they just remote extensions of the parent plant? Will they mature and flower at about the same time as the original plants?


I think they would be counted as new plants, although they are an exact copy or clone of the mother plant. They will behave according to their own surroundings and circumstances. Best of luck with your basil growing!

Creating new plants

I bought a basil plant, and now it's very big and healthy. I wonder how do you regrow a new plant from an old one?


As question 12 illustrates, it's quite easy to take cuttings from basil and produce new plants. Just put the cuttings in water or potting compost until roots form and then put each rooted cutting into its own pot. If you want to keep your big basil plant going through winter, cut it back and place it on a windowsill with plenty of light. It should be happy over the winter months and you can still take leaves from it as when you need them.

Using basil seeds

I have been given a large amount of basil plants that were pulled out of a friend's garden. I have frozen all the pretty leaves and dried those that were turning brown. My question is I have so many seeds, can the seeds be used in cooking to flavour meat or poultry as they are very aromatic?


Basil seeds do have a culinary use (going by the names sabja or tukmaria seeds), although I've never used them in this way myself. They are an ingredient in some Asian drinks and desserts, for example sharbat-erihan (basil seed sherbet) and faluda (a cold milk dessert). As far as I know, the seeds have to be soaked in water and they become rather jelly-like. I'm not certain this applies to all varieties of basil, so you would be advised to do more research on this subject before ingesting the seeds.

Basil berries?

My basil plant has berries, is this normal?


Assuming a basil plant survives long enough to flower, it will have white or, in the case of purple basil, lilac-coloured flowers. When the flowers die off, the plant will develop small black berries which contain basil seeds.

Basil leaves curling

My potted lemon basils are now over 8 inches tall, I've pruned them a couple of times, and they seem to be doing relatively fine, except for the leaves don't seem to be growing as big as before, and curling at the edges. Is there something wrong with them?


In parts of the world where basil is grown as an annual, especially when they are grown in pots, they will deteriorate towards the end of the season before dying. The plants can become leggy and also the leaves get smaller and lose some of their flavour, at least in my experience. So, unfortunately, what you're experiencing with your lemon basil is likely to be nature just doing its thing.

Basil allergy

Can people have an allergy to basil plants?


I am in no way experienced in this matter, but after a brief search on the internet, it appears that people can be allergic to basil.

Using basil blooms

I had basil planted, along with my tomatoes last year in a huge pot that I purchased from Lowe's, we had the coldest winter we've had in many years down here in the South, last winter. All of my basil froze and I assumed they were gone, so I planted more seeds this spring. The black pot basil came back with a vengeance, lol. Now I have basil everywhere. My question is are the blooms edible also and can they be put into salads?


Hi, I believe that some basil blooms are edible, although I haven't tried them myself. They are said to have a subtle flavour and are good in salads and can be used to make a basil tea.

Unseen pests

I have a basil plant that I recently bought and it sits on my kitchen table. Each morning I see something has been eating my basil during the night, all the windows are closed. What could it be?


The only thing you can do in this situation is to monitor the plant. Have a good look under the pot, under the rim of the pot and in the top soil to make sure that a small snail or slug has not come in on the pot. The next thing to do is to look under every leaf and all over the plant to make sure there aren't any small snails, slugs or caterpillars there. It's highly unlikely that whatever is eating the leaves originated in the house. If the basil is near other plants it would also be worth monitoring them.

Leaf-eating pest

Hi I'm Alge, I live in Melbourne ...I'm currently trying to grow basil but am getting problems with pests. At first I thought it was just snails and slugs but I have built fences with soft drink cans cutting teeth in the top and folding them out but now I seem to still be getting something eating them - this time it's whole or half leaves being cut/eaten of the plants and holes in the leaves. Does anyone know anything that will help?


I'm not familiar with pests in Australia but I know from experience that slugs and snails are very capable negotiators of barriers, so it might well be them eating the leaves. Otherwise, there may be some other leaf-hopping, leaf-cutting pest causing the damage. As ever, vigilance is the key, study the plants everyday, look under the leaves and around the stems and look in the soil to make sure there aren't any pests in hiding.


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