16 Mistakes Everyone Makes When Growing Basil

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Basil may be one of the more popular herbs to grow, but that doesn't mean it's easy. If you've ever tried to grow it and ended up with leggy stems, bitter leaves, or learning what "bolting" means the hard way, you know growing basil means making mistakes. Unfortunately, even though it's a kitchen staple, growing basil plants takes a little panache, and knowing the most common mistakes gardeners make ahead of time can save you from countless batches of bitter pesto.

That's why we're breaking down some common mistakes we see gardeners making when adding basil to their garden. We know this list may seem overwhelming — is there anything that basil does like? — but once you know the signs to look for, you'll be able to apply those tricks across the board. We'll break down what's causing the problem and how to fix it, too, so that you can correct any mistake you recognize here ASAP to keep your basil harvest as bountiful as ever.

One of the fastest ways to send your basil plant to the compost bin is by giving it too much water. It might feel counterintuitive since basil can look mighty dramatic on a hot summer day, but giving it too much water creates a perfect storm for problems. Basil roots are sensitive, and when the soil stays moist, they're at risk of drowning due to a lack of oxygen. On top of that, consistently soggy soil invites fungi that can cause leaf spots, wilting, and other oh-so-fun diseases to deal with.

The best way to avoid overwatering is to give your basil a balanced soil blend that drains well. Choose containers with drainage holes, or pick a spot in your garden that has chunky soil that feels loose and not compact. You can always add things to your soil to make it easier for excess water to drain away, like perlite or coco coir. We like Gerta's 10 Quarts of Organic Perlite because it's inexpensive and comes in a variety of sizes, so you can pick the right granule size for your garden. 

Just like overwatering, letting your basil plant dry out too much is a problem. Basil doesn't handle water stress well, so when the soil is tapped out of moisture, the plant reacts fast by wilting, yellowing, or stunting its growth. Gardeners have also noted that water-stressed basil tends to taste more bitter, pretty much defeating the purpose of growing it at all. Plus, hydrophobic soil — soil that repels water instead of absorbing it — can make it even harder to correct the mistake, so save yourself the aggravation and learn how to water basil properly.

How often to water basil is a tricky question because it varies based on your growing conditions. A drip irrigation system is great for those who don't trust themselves to stay consistent — it keeps the roots hydrated and can work for in-ground or container plants. For gardeners who want a low-maintenance option, products like the Flantor Garden Drip Irrigation Kit can help deliver steady water right where it's needed and can be used in garden rows or individual pots.

We know that grabbing the hose and doing a few once-overs on the garden seems easiest, but you're setting yourself up for heartbreak. When water splashes the leaves, two problems happen. First, not enough water gets down to the soil where it's most needed, and it ends up evaporating instead. Second, water droplets that stay on the leaves are like a buffet invite for fungi, opening your basil up to some gnarly infections, like the aptly named "basil downy mildew." In the best-case scenario, your basil leaves look spotted and sickly. In the worst case, you've got a full-blown fungal outbreak.

Fixing this is simple: Keep water focused on the soil instead of the leaves. To do this, either point the hose lower to the ground or install drip irrigation or soaker hoses. For container plants, try using pots that have water reservoirs at the bottom and add water there, or use a narrow-spout watering can and point it near the base of the plant. The more you're able to break the overhead watering habit, the happier your plants will be.

Did you know basil is part of the mint family? Many mint brethren like cool temperatures and partial sun, but basil is the black sheep of the family because it likes plenty of light and warm, sunny days. Without at least six to eight hours of light, basil tends to get leggy, lose its flavor, and bolt quickly. 

The trick to growing basil outside is to make sure it's living in the sunniest spot you've got and not tucked under the canopy of taller veggies, like tomato plants. If you're growing your herb garden indoors, unfortunately, that window sill most likely isn't bright enough for basil, so you'll need to supplement with grow lights. Try using a compact one that stakes right into the soil, like Qicodu's Full Spectrum Grow Light for Potted Plants, and give it around 10 to 12 hours of light. You may also want to space your potted herbs apart so that basil's extended light bath doesn't affect more shade-appreciative plants like parsley or lemon balm. 

One of the mistakes gardeners unknowingly make with basil starts in the grocery store. Those so-called "ready to pick" basil pots you see in the produce section are often multiple seedlings crammed into one tiny container. Sure, it looks lush for a bit, but leaving them all in that pot sets your basil up for a struggle. Overcrowded basil doesn't just compete for nutrients and water; it also has reduced airflow, creating the perfect conditions for fungal diseases. Even if you're growing basil from seed, planting too close together will have the same effect: weak, spindly plants that never reach their full potential. 

The good news is that it's easy to fix overcrowding. If you've picked up a potted basil from your supermarket, remove the plant from the pot and carefully separate the seedlings, then repot them into their own containers. In the garden, thin or transplant seedlings so that there's 8 to 12 inches of breathing room between the plants, which will ensure good airflow and reduce the risk of a fungal outbreak.

One of the most common ways people sabotage their basil is with bad pruning techniques or no pruning at all. For example, cutting into the woody part of the stem near the base is a bad way to prune because it's likely that stem isn't coming back. Woody stems don't grow new leaves the way the more flexible, supple branches do. If you end up pruning your basil plant wrong, you'll most likely get less foliage and weak growth.

The only thing you need to do to avoid this is to prune regularly, the right way. Always cut just above the leaf node because this will encourage new side shoots, which means more leaves. Early in the season when your basil is only 4 to 6 inches tall and has a few leaf sets, pinch the top stem off; this will force branching. After that, pick your basil regularly every few weeks or so, removing about one third of the plant. If you get this right, you'll double your harvest and your basil plant will be a bushy, happy little dude. 

A lot of gardeners think it's smart to start picking basil leaves low on the stem, near the bottom, but this tends to backfire. We get why you might think to leave the top leaves alone; they're most likely smaller and still look like they're growing. But those older, lower leaves are closer to the base, which means the plant is using them for a lot of its core strength and energy. Removing them too early can weaken the stem, reduce photosynthesis, and make the plant less vigorous. Also, harvesting low leaves can expose stems to soil splash, pests, and disease.

Instead, wait until your basil has at least four "true" leaf sets, then begin harvesting by cutting or snipping leaves just above an upper pair of leaves and not from the bottom two-to-four leaf sets. Focus on the top and sides of the plant first, because this encourages new growth and keeps the basil full and bushy. Oh, and always use clean scissors or garden shears to make clean cuts, leave enough foliage for the plant to recover, and try not to take more than one third of the plant at a time. Do this right, and you'll get more fresh basil in your kitchen and fewer sad-looking stems.

Basil is about as cold-sensitive as plants get, which makes leaving it outside too early in the spring or too late into fall a common mistake. It's such a diva that even a light frost can kill it overnight, while temperatures below 40 degrees Fahrenheit will discolor the leaves and damage the plant. If your plant turns black and mushy, it's likely accrued some frost damage and your harvest is probably lost. 

To protect basil, timing is everything. Only plant it outdoors once you're certain all danger of frost has passed. If you see a surprise cold snap in the forecast, cover your basil with a cloche, frost blanket, or even an overturned bucket for the night. And when fall approaches, plan on harvesting the whole plant before temperatures dip below 40 degrees Fahrenheit. If your plant is indoors, keep it away from drafty windows or air conditioning vents. 

Fertilizer can feel like a quick fix to get bigger, lusher basil, but too much of it, particularly nitrogen, will backfire. Yes, basil is a heavier feeder compared to some herbs, but overdoing it pushes the plant to pump out lots of weak, watery growth at the expense of flavor. Leaves from overfertilized basil often taste bland or bitter, and the plant itself becomes more prone to disease because it's focusing on rapid green growth instead of resilience. Essentially, instead of a flavorful harvest, you get a diluted version of basil.

The trick to fertilizing basil right is moderation. Basil likes consistent nutrition, so start with a well-balanced soil mix and supplement with a gentle, balanced fertilizer every few weeks during the growing season. Go easy on high-nitrogen formulas and instead use something labeled for herbs or vegetables to avoid overpowering growth. TPS Nutrients Herb Plant Food has amazing reviews and comes in a variety of sizes so you won't get stuck with a giant bottle if you don't need it. If you notice your basil leaves looking pale or small, a light feeding can help, but if the leaves are already large and lovely, resist the urge to add more.

One of the deadliest threats to basil isn't bugs or bad weather, it's basil downy mildew. This airborne disease shows up as yellowing leaves with a gray fuzz underneath, and once it takes hold, the plant's pretty much done for. The saddest part is that sweet basil, the kind most people grow for classic pesto, is the variety most vulnerable. If you stick only to these susceptible types, you're rolling the dice on whether disease sweeps through your whole crop, especially in humid regions.

Thankfully, science has come to the rescue with basil varieties that are less prone to mildew. Thai basil, lemon basil, cinnamon basil, and spicy globe basil all tend to hold up better, while new disease-resistant cultivars are being bred specifically to fight downy mildew. If you're attached to the flavor of sweet basil, try mixing it in with sturdier varieties so one outbreak doesn't wipe out your entire harvest.

If you've ever noticed your indoor basil looking like it's trying to escape through the window, you've seen what happens when potted plants aren't rotated. Basil leans hard toward its light source and without a little help, it ends up lopsided, weak on one side, and stretched out instead of bushy. Over time, that uneven growth can make the plant more fragile and less productive, which means fewer leaves for your kitchen.

All you need to do to fix or prevent this is to rotate the pot about a quarter turn every week so all sides get equal access to light. This helps the plant grow upright and balanced rather than straining in one direction. If you're using grow lights, you can get away with rotating less often, but it's still worth checking how your basil leans. A little rotation goes a long way toward keeping your plant sturdy, symmetrical, and ready for plenty of harvests.

We know, basil has the prettiest little flowers. But letting the plant flower is actually one of the fastest ways to ruin your harvest. Once flowers emerge, basil shifts its energy away from producing leaves and into making seeds. That means the foliage left behind often turns bitter, tough, and sparse. If you don't catch it early, your lush basil can decline almost overnight into a spindly, flavorless plant.

To prevent this, you'll need to keep an eye out for flower buds and pinch or snip them off as soon as they appear. Regular pruning throughout the growing season keeps the plant focused on leafy growth instead of reproduction. Don't be afraid to harvest often; it not only gives you more fresh basil for cooking but also keeps the plant in its most productive, flavorful stage right up until the first frost.

Basil may love warm temperatures, but combining that with too much humidity is a fast track to Diseasetown. The pathogen that causes downy mildew thrives when humidity hits 85% or higher inside the plant canopy, and once it's in, your basil leaves can yellow, wilt, or develop that telltale fuzzy gray underside. It's especially common indoors or in greenhouses where stagnant air traps moisture. Outdoors, overcrowding or watering in ways that keep leaves wet for hours can have the same effect.

The solution is to keep the air moving and the leaves dry. Watering from the base instead of overhead will go a long way to keeping humidity down since the water will be trapped in the soil, taking longer to evaporate. Space plants far enough apart for airflow, and if you're growing indoors, add a small fan or dehumidifier to stop moisture from hanging in the air. Even simple steps like watering in the morning so the sun helps dry the leaves can help keep basil mildew-free. 

Skipping the mulch might not sound like a big deal, but it can make your basil work harder than it needs to. Mulch helps lock in moisture, regulate soil temperature, and suppress weeds so your basil can focus on leafy growth. Without a protective layer over the soil, the water evaporates faster, meaning the roots dry out faster, too. Bare soil also creates space for weeds that compete with your basil for nutrients and moisture, leaving you with weaker, less productive plants. Over time, that lack of insulation stresses your basil and reduces both its hardiness and yield.

To fix this, just add a light layer of organic mulch around the base of your basil plants. Straw, shredded leaves, or even untreated grass clippings all work well.  Just be careful not to pile mulch directly against the stems, since that can trap moisture and invite rot. 

Not all seeds are created equal, and growing basil from seed with poor-quality ones is a mistake that can doom your plants before they even sprout. While basil seeds can remain viable for years, they get slower and less reliable the older they get, so you may be waiting weeks only to find they'll never sprout. And it's not just about sprouting late: In the past, contaminated basil seed has fueled outbreaks of downy mildew, a disease that can wipe out whole crops, so poor seed quality can bring bigger headaches than you might expect.

The best fix is to be choosy about where you get your basil seeds. Stick with reputable suppliers that test and handle their stock carefully to minimize the risk of disease contamination. If you're using older seed packets, do a quick germination test by planting a few in a damp paper towel to see how many sprout before you commit to a whole tray. And if your basil seedlings don't appear within about 10 to 14 days, cut your losses and buy some seedlings from your local nursery.

It's easy to plant basil into any open spot in the yard or a container by the driveway, but where you plant it matters more than you'd think. Basil leaves are edible straight off the plant, which means whatever settles on them ends up in your kitchen too. Planting too close to busy streets or driveways leaves the foliage exposed to exhaust, dust, and grit that aren't just unsavory — they're unhealthy. Even seemingly harmless spots like near footpaths or low garden edges can leave basil constantly coated in dirt kicked up by wind and rain.

To keep your basil clean and safe to eat, choose a site with clean soil and some distance from pollution sources. Raised beds and containers are a great option since they lift the plants up and away from splash-back when it rains. For indoor plants, keep basil away from drafty windows that may bring in road dust, and rinse leaves occasionally if they've collected residue.