Basil with yellow leaves: causesand solutions. What to do if basil leaves turn yellow and most importantly, why does basil turn yellow? Here is all the useful information that will save our basil plants.
Thebasil (Ocymum basilicum) is an annual herbaceous plant that reaches and exceeds 60 cm in height in good cultivation conditions.
Basil with yellow leaves, causes
Yellowing of the leaves can have multiple causes, but the most common are attributable to a single factor: water!
Case No. 1: excess limescale in the irrigation water
In the case of yellowish leaves, with veins that remain evident, the cause of yellowing could be chlorosis. The chlorosis of basil, like that of many other plants, is linked to a nutritional deficiency, in particular it is a scarce or absent assimilation of iron and other micronutrients of the soil. Chlorosis is an effect of the excessive administration ofcalcareous water. This means that you have irrigated your basil too much by using highly hard tap water. Excess limestone in the soil creates an imbalance in the soil pH reaction, indirectly causing iron, potassium, zinc or nitrogen deficiencies.
For a prompt intervention, you can administer an iron-based fertilizer. The "chelated iron" fertilizers are administered by burying them in the ground quickly because the light tends to degrade this particular fertilizer. The chemical composition of these compounds makes iron available also in calcareous soils, i.e. those soils responsible for ferric chlorosis.
To get an idea of the products on the market and choose the one with the best price, we refer you to the Amazon page dedicated to fertilizers based on chelated iron.
Case No. 2: over watering, too wet soil
Basil can turn yellow even after long summer rains. In case of water stagnation or excessively moist soil (when the soil remains wet for too many days), they begin toyellow leavesplaced at the base. Also this time the cause is water but limescale is not involved here: rain or too frequent irrigations keep the soil moist, suffocating or even causing rot in the basil's root system.
Other possible causes. Case No. 3: insufficient substrate or too much sun
if the basil plant was purchased in a pot and you have never transplanted, do it ASAP! When you buy a plant, it must be transplanted by replacing a large part of the soiloriginal with a soil just as suitable for cultivation but richer in nutritional elements. As the basil grows, the old basal leaves turn yellow and need to be cut.
An excess of sun and wind tends to dehydrate the seedling causing a yellowing of the leaves, but in this case the yellow leaves only the apical ones, that is, more exposed to the outside while in all the other cases listed so far, the basil turns yellow starting from the basal leaves.
Basil with yellow leaves, what to do
To solve the problem ofbasil leaves that turn yellowad hoc measures must be implemented based on the cause.
In the first hypothesis (irrigation with excess limestone) it will be sufficient to perform more rational irrigations. Irrigate the plant only when it really needs it and above all do it with non-calcareous water. Use rainwater to irrigate basil (for some advice, read the articlecollect rainwater to water the plants), or use tap water but with a little trick: fill a basin and leave it on the balcony, in the open air, for at least 24 - 48 hours before irrigation. The harder the water (calcareous), the longer the waiting times will be.
If the basil leaves have now turned all yellow, proceed to make an iron-based fertilizer.
In the second hypothesis (excess of water), immediately transfer the plant to a very sunny place so as to allow the soil to dry out. Suspend watering for a couple of days, until the soil has mostly dried up. At this stage it is important to always empty the saucer. Learn to administer water more rationally, respecting the water needs of the plant without overdoing it. In extreme conditions, if the basil has turned all yellow, you can repot it by replacing much of the wet soil with dry substrate.
In the case of the third hypothesis (poor substrate), if you grow several basil plants in the same planter, transplant them at a distance of about 30 cm from each other or give the basil more space and soil.