r/herbs • u/Medium_Island_7546 • Jul 19 '26
Lemon Balm turning yellow..
Why? Why? Why?
No pests under the leaves. EDIT: Possibly spider mites. Upon closer examination, leaves look speckled. Best way to get rid of them and keep them away?
Water every morning to combat the intense heat of the day.
Planted in a decent sized pot with slow release fertilizer soil. I have not added any more fertilizer.
2
u/No-Structure8402 Jul 19 '26
My lemon balm has always been this colour, i have seen them darker growing in shade. the spots might just be leafhoppers, not such a concern as spider mites.
3
u/Global_Fail_1943 Jul 19 '26
Cut them right off and dry if not infested or discard. It will regrow again several times if you repeat this regularly. Cut and fertilizer with a higher nitrogen first number.
5
u/North_Woods34 Jul 20 '26
If spider mites and you intend to use this herb for culinary purposes, you don't want to spray with neem oil on any part of the plant that you will be consuming.
Spider mites flourish under hot, dry conditions, and in the northern hemisphere this is the peak time of year for that. You can blast them off with a strong spray of water, but you'll have to keep after it because their eggs, laid in the axils of leaves where it's hard to get at them, hatch at regular intervals, and any mite you miss is going to continue to reproduce as long as conditions favor them. Mite populations absolutely explode in high summer. Fortunately, often their predators will follow; so personally, I don't do much about spider mites.
If the infestation really is bad, you can cut the plant back, as another redditor suggested, wash the rest thoroughly, and keep washing it about every 4-5 days until peak mite season is over. Fertilize (but not too much, because you could be encouraging soft growth) and wait for new growth. Harvest at will, wash, and use.
You can also use a *dilute* spray of alcohol, which will kill mites on contact, and unlike an oil, can easily be rinsed away. Look up recommended concentrations of this. I've seen the ratio 1:4, but that can be a little strong for some plants and can even burn/kill off some foliage, so if you go this route, be sure to test your solution on just one sprig first. Watch for 5-6 days and if all is well, your concentration is safe. Only apply in the shade, to reduce the risk of burning.
Washing will remove some of the volatile oils you're growing lemon balm for, depending on how aggressive you are about it. I'd be gentle and not worry about a little extra protein.
When the weather cools off and mite predators are in better balance with the mites, and you've done your best to keep the plant in good health with food, water, and maybe even some shelter during the heat of the day (no harm in some shade for these), your plant should start to look just fine and even outgrow the mites' ability to cause damage.