Leggy Herbs: Why They Stretch and How to Fix Them

Your basil shot up but ended up tall, skinny and sparse. Your parsley flops toward the window. Your mint turned into a few long, awkward stems. If your herb garden looks like this, it isn’t sick. It’s leggy, stretching to find light.

Leggy herbs are almost always a sign of too little light. To fix them, move the pots to your brightest spot (at least 6 hours of direct sun, ideally a south-facing window) or put them under a grow light for 12 to 14 hours a day.

Then prune: on basil and mint, cut each stem just above a pair of leaves; on parsley and green onions, harvest the longest stems. Stretched stems won’t shrink, but the plant will regrow shorter and bushier.

In this guide, you’ll learn why herbs get leggy, how to prune each one and how to keep them compact from now on.

Why do herbs get leggy?

The technical term is etiolation. When a plant gets less light than it needs, it puts its energy into growing upward to reach the sun. Stems get long and thin, and the space between leaves (called internodes) gets wider. With little energy left for leaves, they stay small and pale.

Think of someone standing on tiptoe to see over a crowd: the plant stretches toward the light and ends up weak.

How can I tell if my herbs are leggy?

• Long, thin stems that can’t hold themselves up.
• Big gaps between leaves along the stem.
• Small, pale leaves, sometimes yellowing.
• A plant leaning hard toward the window.
• Leaves only at the top, with bare stems below.

Compare your plant with this quick table:

Plant part	Leggy herb	Healthy herb
Stem	Thin, soft, long and flopping	Sturdy, thicker and upright on its own
Space between leaves	Wide, with bare sections of stem	Short, with leaves close together
Leaves	Small, thin and pale green	Larger, firm and deep green
Shape	Tall, sparse and leaning toward the window	Short, full and rounded
Aroma	Weak	Strong, especially when you rub a leaf

What causes leggy herbs besides low light?

Cause	How to spot it	What to do
Not enough light	Pale, thin plant leaning toward the window	Move to the brightest spot or add a grow light
No pruning	Basil or mint growing as one tall stem	Pinch or cut the tips just above a pair of leaves
Warmth with low light	Pot near the stove, a heater or in a warm, dim room	Move to a brighter, slightly cooler spot
Overcrowded seedlings	Many thin seedlings competing in one pot	Thin them out or separate into more pots
Bolting (starting to flower)	Central stem shooting up fast with buds at the tip	Pinch off the buds. With cilantro, harvest and resow
Too much fertilizer	Fast, soft growth with big, floppy leaves	Feed less often and water well to flush the excess

How much light do herbs need?

Most herbs need at least 6 hours of direct sun a day. Basil, rosemary, thyme and oregano want 6 to 8 hours. Parsley, green onions, mint and cilantro can handle a bit less, but they’ll still stretch in a dim corner.

A window that looks bright to us can be weak for plants. Light drops off quickly as you move away from the glass.

That means a pot six feet from the window gets far less than one on the sill. In the Northern Hemisphere, south-facing windows get the most sun, followed by west and east. North-facing windows are usually too dim for herbs.

What if my home doesn’t get much light?

A grow light solves it. Hang it about 6 to 12 inches above the leaves and run it for 12 to 14 hours a day. A plug-in timer makes it automatic. In winter, when days are short, a grow light makes the biggest difference. See more in how to grow herbs in winter.

How to choose a grow light for herbs

You don’t need expensive equipment. For a small kitchen herb garden, a simple light makes a huge difference. Here’s what to look for:

• Shape: screw-in bulbs work for one or two pots. LED bars or strips are better for a row of pots on a windowsill or shelf. Panels cover larger setups.
• Light color: choose “full spectrum” lights that look white. Your herbs will look natural, and your kitchen won’t glow purple like it would with pink grow lights.
• Actual wattage: check the real wattage on the box, not the “equivalent” number. For two or three pots, about 10 to 20 actual watts is usually enough.
• Adjustable height: a stand or clamp that moves up and down helps you keep the light close to the leaves as the plants grow.
• Timer: many models include one. If yours doesn’t, a plug-in outlet timer does the job.

If your herbs keep stretching toward the light, it’s too far away. If the top leaves look bleached or scorched, it’s too close, so raise it a bit.

Don’t move a leggy herb into strong sun overnight

A plant that spent weeks in a dim corner has thin, tender leaves. If it goes straight into harsh midday sun, it can scorch, with white or brown patches that dry out.

Make the move gradually. For the first few days, place it where it gets gentler morning sun. After about a week, it can go into your sunniest spot. With a grow light, start with the light a little higher and lower it over several days.

How to prune leggy herbs

Pruning is what turns a tall, skinny herb into a short, bushy one. When you cut the tip of a stem, the plant switches to growing from the tiny side buds below the cut, so one stem becomes two.

1. Fix the light first. Otherwise the plant will just stretch again.
2. Use clean scissors or snips.
3. Find a pair of leaves about halfway down or in the lower third of the stem.
4. Cut just above that pair of leaves, leaving the tiny buds where the leaves meet the stem.
5. Always leave some leaves on the plant. They feed it while it regrows. Don’t remove more than about a third at once.
6. Wait one to two weeks for new side shoots to appear.

If your herb is very leggy, prune in two rounds, two to three weeks apart, instead of cutting it all back at once.

How to turn the cuttings into new plants

Your pruned stems don’t have to go in the trash. Basil and mint root very easily, and each cutting can become a new plant that’s shorter and bushier than the original.

1. Pick healthy stems about 4 inches long.
2. Strip the leaves from the bottom half, keeping only the top ones.
3. Place them in a glass of water so the bare part is underwater and the leaves stay dry.
4. Keep them somewhere bright, but out of harsh direct sun.
5. Change the water every two or three days.
6. When the roots are 1 to 2 inches long, usually after one to three weeks, plant them in a pot with light potting mix.
7. Keep the soil evenly moist for the first week and give the new pot your brightest spot.

One leggy basil plant can easily turn into two or three new pots.

How to fix each leggy herb

• Basil: responds best to pruning. Cut each stem above a pair of leaves and pinch off flower buds as soon as they show. The cut tips root easily in a glass of water and become new plants. More in how to grow basil in a pot.
• Mint: can be cut back hard, to about 2 inches above the soil, and it bounces back fast. Cuttings root in water too. See how to grow mint in a pot.
• Parsley: has no branches to prune, because the stems grow from the center. Harvest the longest, floppiest stems from the outside in and move the pot closer to the light. New stems will come in shorter. See how to grow parsley in a pot.
• Green onions: thin, floppy leaves mean low light. Cut everything back to about 2 inches and move the pot somewhere brighter. They regrow in days. See how to grow green onions in a pot.
• Cilantro: when the central stem shoots up, it’s usually bolting, which happens fast in warm weather. Harvest what you can and sow a new batch every three to four weeks.
• Rosemary and thyme: stretch when they’re far from the sun. Trim the soft green tips, but avoid cutting into the old, brown woody stems, which rarely regrow. Both need lots of sun to stay compact.

Common mistakes when fixing leggy herbs

• Pruning without fixing the light. The plant regrows, then stretches again within weeks.
• Cutting everything down to the soil. This works for mint and green onions, but basil may not survive it. Always leave a few sets of leaves.
• Fertilizing to “make it stronger.” Fertilizer can’t replace light, and it can make growth even softer and floppier.
• Staking and forgetting. A small stake keeps a floppy stem upright, but it doesn’t fix the cause. Use it only while the plant recovers.
• Crowding pots together. Plants packed tightly shade each other and stretch to compete for light.

Can leggy seedlings be saved?

Yes, if you catch them early. Seedlings started in a dim spot grow thin, wobbly stems. Move them to bright light or under a grow light right away. If they’re crowded, keep only the strongest ones, about an inch apart. For basil seedlings, you can add a little potting mix around the base of the stem for extra support.

How to keep herbs from getting leggy

1. Give herbs your brightest spot, as close to the window as possible.
2. Turn the pots every few days so they grow straight.
3. Harvest often. Every harvest is a small pruning that makes the plant bushier.
4. Pinch off basil flowers as soon as they appear.
5. Go easy on fertilizer.
6. Use a grow light in winter to make up for short days.

Low light can also make leaves turn pale or yellow. If that’s happening too, read our guide to herb leaves turning yellow. And to set up your herbs in the right spot from day one, see our complete kitchen herb garden guide.

FAQ: leggy herbs