Basil, everyone’s favorite culinary herb, can be a finicky one to grow, especially if it’s your first time doing so. If your plants seem to become droopy at certain times of the day, there are a few things you can do differently to avoid this.
Keep reading for 7 reasons your basil plants might be wilting so you can enjoy this delicious herb all season long!
Overwatering
Basil prefers well-drained soil and full sun, which can sound like somewhat of an oxymoron. It is particular about when and how much it is watered. It will show signs of stress if it goes too far above or below that.
Overwatering, especially if you do not have well-draining soil, could cause wilting in your basil. If you notice that your plant also has some yellowing near the base, you may have overwatered.
The Fix
When starting seeds indoors, be sure your cell trays have good drainage and that you provide ample airflow. This will allow the plants to take up whatever water is needed and drain out the rest.
If your plants sit in a tray of standing water all day, the roots could become waterlogged and rot. You never want your soil to be sopping wet, but rather like a brownie consistency – moist to the touch but not oversaturated.
Underwatering
Basil can be started indoors with the assistance of heat mats. These are great tools, especially for northern region growers. Keep in mind that heat mats will dry out cell trays much faster. So, you’ll want to keep an eye on the soil moistness even closer. Dried-out soil will certainly affect germination rates.
Even though it’s a warm weather-loving crop, under-watering basil will have negative effects, including wilting.
The Fix
Once your basil is planted out in your garden, be sure to have a good watering schedule set in place. Keep your eye on the weather conditions. If it will be extremely hot and dry, consider using shade cloth to protect your basil from too much direct sunlight, provide good airflow, and plan to water every day. Just like humans on dry, sunny days, your basil should drink more water to stay hydrated.
During normal conditions, you can water every 2-3 days. Remember, you want the soil to stay moist and should never completely dry out. If you are noticing your plants wilt each day when it is hot and sunny, this is an indication you should water more frequently or perhaps for longer each session.
If you are growing in hardiness zones 7+, you should definitely consider using shade cloth on extra sunny days and watering more frequently. This will help decrease the temperature at the plant level just a bit, which could make all the difference between plants drying out and wilting and thriving.
Pro tip: Watering early in the morning or evening around dusk is best. This allows the soil to soak up the moisture rather than allowing it to simply evaporate in the hot sun at the peak hours of the day.
Disease Pressure
Unfortunately, basil is prone to disease fairly easily, mostly Downy Mildew and Fusarium Wilt. Luckily, some varieties have been bred to be more disease resistant such as Prospera, Rutgers Devotion DMR, and Prospera Compact DMR, which is great for patio growers. Genovese tends to be the most susceptible to Downy Mildew.
The Fix
Airflow, a tidy garden, and proper humidity levels are key to avoiding disease.
You can also plan several successions in case the disease claims some of your basil patch.
Pro tip: Basil grows well alongside lots of other crops, so if you just have a few extra cell trays lying around of it, if something happens, you can just pop them in. If you end up with a lot, when it comes time to harvest, gift some to a friend or neighbor, or make pesto!
Pest Pressure
Aphids, flea beetles, Japanese beetles, and slugs are just a few pests that might go after your beloved basil.
There are a few different things you can try to help with pest pressure, and it really just depends on your scale, set-up, and patience level.
The Fix
This is always a great first line of defense regarding pest control. You could try planting alliums or strong herbs such as rosemary or mint around your basil, as it is believed that aphids do not like the smell and will simply leave the area.
Nasturtium, marigolds, and sunflowers attract aphids, which may seem counterintuitive, but planting them nearby could deter pests from eating your prized basil and instead feed on these other crops they also find delicious.
Last year we discovered that flea beetles really love to feed on an Asian green called Tokyo Bekana. We had planted basil alongside the greens and realized (too late) that we had unintentionally planted a trap crop that kept the flea beetles away from our basil. Now we intentionally pop one of these in between every 5-10 basil plants.
Ladybugs and parasitic wasps can be attracted to your basil patch by planting parsley, calendula, or sweet alyssum nearby. You may also attract green lacewings to the area by planting flowers such as cosmos and zinnias. All of these insects or their larvae feed on aphids. You can also purchase lacewing eggs and ladybugs online.
These are temporary fixes, but if you are in a pinch, try these. Insecticidal soap causes dehydration in pests by removing their protective body coating. You should see a decrease in infestation within 24 hours. Bad cases may require reapplication 3-6 days later. Simply spraying with water will blast the bugs off your plants and allow you to harvest clean leaves, but they will likely return.
There are also sticky traps that bugs will stick to. Keep in mind that the good bugs might get stuck too!
Sluggo is an OMRI-certified organic option if your slug pressure is very high. There are mixed reviews on whether Japanese beetle traps work or simply attract more beetles. We used them last year on our farm and noticed a drastic decrease in damage. I think they’re worth a shot!
Lack of Nutrients
This mostly has to do with basil being planted in a pot that is too small for necessary growth. If you grow basil indoors, be sure you can increase the size of the pots in case the weather doesn’t allow you to put them outside as planned.
The Fix
Adding fresh soil to a larger container makes a huge difference if you need to buy some time before transplanting basil starts. Feeding them with fish emulsion will also add a boost of nutrients and help them hang on until you can transplant them out.
Upon planting out, be sure your soil has been properly amended. Then, in late spring, you can start to feed your basil. They do best with a balanced liquid fertilizer, although it’s really a personal preference if you want to use liquid or granular fertilizer. You can feed about every 4-6 weeks following the instructions of the product of your choice.
A higher level of NPK (Nitrogen, Potassium, Phosphorus) isn’t necessary, so stick to something like a 10-10-10 or 4-4-4 for basil. This will give you lush, fast-growing foliage with enhanced smell and taste.
Transplant Shock
Transplant shock can happen to plants if they are not hardened off properly and experience disagreeable weather conditions soon after transplanting, such as high winds, extreme heat/cold, low soil temperatures, or dried-out roots. If plants are shocked at the time of transplant, you can see adverse effects on your crops’ performance and yields all season long.
The Fix
Harden Off Plants
About a week before your planned transplant date, you should start introducing your plants to the outside world. I find that moving trays outside on a calm and partly to mostly cloudy day works best. It might sound strange, but direct sunlight can shock some plants, so you want to take it slowly.
Other things that might stress your basil plants out are strong wind, hard rain, and harsh sun, so keep your eyes on the forecast and plan accordingly.
Pro tip: On day one of hardening off, try moving trays outside for just a half day and back inside for the night. You can increase their time outside during the day and then at night. This might sound silly, but you wouldn’t send your kid to a big city before teaching them how to ride the subway, hail a cab, and cross a busy intersection first, so don’t force your plants outside before they’ve had a taste of the real world first. This will help them adjust to the elements, bulk up their stems, and become hardier.
It should be noted here that you should pay close attention to the days to maturity and best-growing conditions for each of your crops to ensure seeds are being started at the right time. Too early, and they may become rootbound in their trays waiting to go out. Too late, and conditions might not be agreeable during their most vulnerable time.
Ensure The Soil Is Warm Enough
Each crop has a preferred soil temperature, which is especially important when direct seeding your garden. If the soil is too cold, seeds will not have great germination or could rot in the ground. The seeds that do germinate might have stunted growth, decreased production, and even an increased chance of disease.
Basil requires 75-85° for germination. If you are starting seeds inside, a heat mat will provide you with even, consistent heat, perfect for warmth-loving basil.
If you have a setup that allows you to start your basil plants indoors, it is definitely recommended. Then, once soil temperatures are agreeable and the chance of frost has passed, you can plant them out. Don’t rush your basil. The cold easily damages them, and they will most certainly die if a frost hits.
Pro tip: You can slightly warm up your soil using tarps for a few weeks before directly sowing or transplanting. Also, having a soil thermometer is worth the small investment. This will allow you to be more efficient.
Fluctuations in Temperature
In some regions, temperatures can fluctuate quite a bit in early spring and fall. This could cause stress and wilting in basil plants.
The Fix
Be sure you are doing everything you can to provide consistency, such as covering at night when it is calling for cooler temperatures and shade cloth when it may be particularly hot and sunny. It’s not necessarily that the plants can’t handle the adverse conditions; they prefer consistency.
Final Thoughts
When a plant wilts, it’s trying to tell us something, so when your basil wilts, be aware of what it’s going through and try to combat the situation the best you can.
Plants are resilient and want to live; typically, they can bounce back from some light damage. Do your best to provide basil plants with consistent temperatures, good airflow, balanced fertilizer throughout the year, and well-draining soil, and they will provide you with abundance all season long.
