Basil is a bit dramatic when it comes to the popular herbs and has a tendency to droop quite often, but it can also rebound easily. So let’s say you bought a gorgeous basil with an earthy, Mediterranean cooking-esque aroma and it’s wilting despite your best efforts…why?
I have personally grown basil plants for many years in all kinds of conditions, such as outdoors, indoors on window sills, and even in the ground in my allotment and in my experience, it wilts faster than any other herb, so it’s kind of my early warning system that my herb garden may be under stress.
Fortunately, basil can perk up just as quickly as it wilts, as if nothing had happened!
Here is what is going on with your basil from someone who has identified and dealt with all the causes and solutions I am going to talk about.
The Most Underrated Cause: Sudden Temperature Spikes
This is the number one cause that I want to lead with, because it’s genuinely underrepresented from everything that I have read online (and in the little care instructions that you get with basil seeds) in basil care advice, and it’s caused me more than a few moments of unnecessary concern over the years.
Basil is tropical in origin and prefers warm weather; however, from my own experience growing it, I have found it is surprisingly sensitive to temperature spikes. When the temperature fluctuates upwards, I have seen perfectly healthy, well-watered basil start to wilt despite moist compost.
There can be two things happening here, one of which is the mismatch between the sudden increase in transpiration (water loss through the leaves) and the maturity of the basil roots to draw up enough water to replenish them. If it cannot draw up water quickly enough, the leaves lose turgor pressure and begin to droop.
So in this case, the leaves are wilting to reduce their surface area, which means they lose less water through their leaves during the hottest parts of the day…midday and afternoon sun, which is when I notice my basil drooping the most.
Typically, what I find is that my basil leaves rebound either partially or completely during the cooler temperatures of the evening, which reduces transpiration, and it’s when the roots are able to draw up enough moisture and restore turgor pressure in the leaves so that they perk up again.
It doesn’t mean your basil is wilting and dying, but rather it means it’s responding to conditions exactly as it would with the wilting being a precaution so that it doesn’t dry out completely. It can often cope with these higher temperatures if it is given a chance to acclimate, which obviously doesn’t happen if there’s a sudden temperature increase. In this situation, the most helpful things you can do for your basil are…
- Move your pot-grown basil out of direct midday afternoon sun during a heatwave or sudden spike in temperatures. Almost always, morning sun is fine and actually the best (as the basil can photosynthesise without the stress of high temperatures), whereas harsh afternoon sun on a 30°C day is a recipe for wilting basil.
- Water in the morning rather than the evening so that you charge the soil with moisture for when the temperature climbs.
- Don’t overwater in a wilting-induced panic if the soil is already moist and the plant is drooping due to temperature; adding more water doesn’t help and risks root problems!
The Most Common Cause is Underwatering
Look at the leaf size of basil compared to most herbs. It has a larger size in proportion to its roots, therefore it transpires quickly and can draw up moisture from the soil faster and more ruthlessly than most herbs.
This is why you can water fennel and chives the same amount as your basil, and they are perfectly fine, but the basil is the one to complain.
Your basil is the one herb in your garden that is going to need more watering than the others.
The good news is that underwatering is the simplest and most reversible cause of wilting basil.
Here is how I perk up my underwatered basil.
- Water deeply, as the goal of watering should be that the soil is evenly moist. This means watering enough so that water drains from the drainage holes in the base of the pot.
- Pick up the pot, and it should be heavy after watering. If it’s light, then you have only watered the surface, or the soil is repelling water off the surface without absorbing it properly, in which case I place my basil plants in some water (either in a basin or a wheelbarrow) and allow the soil to draw up moisture through the drainage holes in the base of the pot.
- Allow the pot to drain completely, and don’t leave it sitting in a waterlogged saucer for example, as this can cause root rot.
- Check the soil daily in warm weather, as in my experience, my basil in a small pot on a sunny windowsill can dry out completely within around 24 hours in summer, so it can need very regular watering.
If your basil wilts repeatedly despite you watering it regularly, the size of the pot is almost certainly the issue, which brings me to the next point…
The Pot Problem Nobody Talks About Enough
If you bought your basil from a supermarket, as I do, when it looks so tempting and smells amazing, the reason it looks so good is that the basil is not one plant, but many seedlings actually crammed tightly together in one pot, and it’s grown very quickly in commercial greenhouse conditions in a small amount of compost that is getting more delepeted and root bound by the day.
This is the reason why supermarket basil wilts and dies so often, as there simply isn’t enough soil volume to retain adequate moisture, and the roots are competing intensively with each other for nutrients, and therefore no amount of considered watering can compensate for this.
The fix?
What yyou need to do as soon as you get home with supermarket basil is to split the seedings and repot them. What i do is get the basil out of the pot and gently tease the roots apart its around 2 or 3 seperate clmps and pot each one into its own larger container with more compost so it can finally have access to the water and nutrients it needs.
Within a week or tow you’ll see the difference with stronger stems and larger leaves, and of course they are less likely to wilt between each watering.
I do this all the time, and the basil that I split like this outlives the non-split basil by weeks, and I get a bigger harvest… more value for money!
Overwatering and Poor Drainage
This is so counterintuitive, but overwatering actually produces the same symptoms as underwatering, with drooping stems and wilting leaves!!
This is due to the fact that waterlogged roots do not have access to oxygen, which the needs for root respiration. In waterlogged soils, the root cells break down and begin to rot. Of course, damaged roots cannot transport water effectively, so ironically, despite being in wet soil, the basil cannot draw up the water or nutrients it needs.
The distinction between overwatering and underwatering wilting is usually most visible in the leaves and soil…
- Underwatering the leaves are dry, slightly crispy at the edges, and the soil is bone dry, with the pit feeling light, and the plant perks up quickly after watering
- Whereas overwatering, the leaves may look soft, pale, or even slightly translucent, the soil is persistently wet, and the basil does not recover after watering and may smell slightly musty (like something bad in the fridge) at the roots.
If you think you’ve overwatered your basil, then stop watering and move the basil to a place with good air flow.
Healthy roots look nice and white and feel firm; brown, mushy, bad-smelling roots indicate rot. If rot has set in, then remove the affected roots and allow the basil to dry before repotting into new compost, and I’d add some perlite for better drainage.
This isn’t guaranteed to work, but it gives the basil a good shot at recovery.
Heat Stress From a South-Facing Windowsill
Our basil plants love warmth and light, but a south-facing windowsill in mid-summer can create incredibly hot conditions that are too much and result in wilting leaves.
I have found that glass can increase the heat of the microclimate of a windowsill a long way.
Signs that heat stress rather than water stress is the issue are that the soil is moist and the basil wilts at the hottest parts of the day, and the leaves develop pale, dry patches where the sun has scorched them.
This is distinct from the temperature fluctuation I described earlier, as this is sustained heat and light.
The solution is simple… You just need to move the basil back from the glass a bit, or relocate it to a spot with bright, indirect light during the hottest weeks of summer. I have found that an east-facing windowsill that gets morning sun but avoids the intense afternoon heat is often the best.
A Quick Diagnostic Guide
Is it wilting in the afternoon on a hot day, but recovers by evening, soil is moist… this is the temperature spike response, which is normal, and you need to improve airflow, reduce afternoon sun exposure.
Wilts consistently, soil is very dry…then it’s underwatering, or the pot is too small, so you need to water thoroughly, consider repotting.
Is it wilting despite moist soil? Do the leaves look soft or pale? Overwatering or root rot, so stop watering, check roots, and improve drainage with perlite.
Wilting in direct sun, leaves have pale patches… This is heat stress from intense sunlight, so move away from direct afternoon sun.
The Short Answer
Basil wilts for specific and generally identifiable reasons — and most of them are fixable once you know what you’re looking at. In my experience, the temperature fluctuation cause is the one that catches experienced growers off guard most of the time, because the plant looks distressed when it’s actually just responding sensibly to a sudden change in conditions in its usual way.
If your basil droops on a hot afternoon and bounces back by morning, then don’t panic, but if it’s wilting regardless of temperature and the soil is either bone dry or persistently wet, that’s when to act.
Is your basil wilting, and none of these quite fit? Drop a comment below with the details, and I’ll help you diagnose it.