Countertop HarvestBy the Countertop Harvest team · Last updated · How we choose products
Tap what you see, answer one more question, and the Herb Doctor gives you the likely cause and the free fix to try first. Each step links to the full guide and its sources, so you can check the reasoning.
Step 1
What do you notice first?
Step 2
Is the soil still damp a day after watering?
Step 2
Push a finger into the soil. How does it feel an inch down?
Step 2
What do the pests look like?
Likely cause
Not enough light
Leggy stems that lean toward the window and smaller leaves are classic low-light signs (Penn State Extension).
Try this first (free)
- Move the pot to your brightest window. Most herbs want about 6 hours of direct sun (Penn State Extension), and Iowa State says around 8 indoors (Iowa State Extension).
- Rotate the pot often so every side gets light (Penn State Extension).
- Cut each stretched stem just above a leaf pair. Stretched stems won’t shrink, but two new shoots grow from the cut.
If that’s not enough
Add a full-spectrum grow light on a timer for 12–16 hours a day, close above the leaves (Iowa State Extension). Iowa State lists leaf scorch and bleached leaves as signs a light is too close (Iowa State Extension).
Read more: why herbs get leggy · how much light herbs need
Likely cause
Probably low light
Iowa State lists pale or yellowing foliage and leaf drop among the signs herbs need more light (Iowa State Extension).
Try this first (free)
- Move the plant to a brighter window and rotate it (Penn State Extension).
- Keep watering only when the top inch of soil is dry, so you don’t add a water problem on top.
If that’s not enough
In a smart garden or hydroponic kit, check the water level and the plant-food schedule too. Our nutrients explainer covers the basics.
Read more: how much light herbs need
Likely cause
Too much water
Yellow lower leaves with soil that stays damp usually mean the roots are sitting wet.
Try this first (free)
- Wait to water until the top inch of soil is dry.
- Water until it runs out the bottom, then empty the saucer.
- If the pot has no drainage holes, move the plant to one that does.
If that’s not enough
If stems are soft at the base, check for root rot (see below).
Read more: why indoor basil dies · root rot
Likely cause
Thirsty plant
Drooping with dry soil is the easy one.
Try this first (free)
- Water thoroughly until it drains from the bottom.
- Check again every few days with your finger. Small pots in a sunny window dry out fast.
Read more: how to grow basil indoors
Likely cause
Possible root rot
Wilting at the base with mushy stems and wet soil points to rotting roots.
Try this first (free)
- Slide the plant out and look: healthy roots are firm and pale, rotten ones are dark and soft.
- Trim the rotten roots and repot in fresh, dry mix in a pot with drainage holes.
- Water lightly until it recovers.
If that’s not enough
If most roots are gone, start fresh. A new packet of seed or a split grocery-store plant is often quicker than a rescue.
Read more: why indoor basil dies
Likely cause
Fungus gnats
Tiny dark flies around the pot. The larvae live in moist potting mix and feed on organic matter and root hairs (Mississippi State Extension).
Try this first (free)
- Let the soil dry between waterings (Mississippi State Extension).
- Lay yellow sticky cards flat on the soil to catch adults (UConn IPM).
- Keep it up for a few weeks: the life cycle is about 21 days (University of Arizona Extension).
If that’s not enough
Drench the soil with a BTi product, which Mississippi State calls the most effective treatment (Mississippi State Extension). For adults on the leaves, Lost Coast Plant Therapy’s label covers fungus gnats, and it’s the spray we use on our own herbs (Lost Coast Plant Therapy). Lost Coast on Amazon →
Read more: get rid of fungus gnats
Likely cause
Spider mites
Fine webbing and pale speckles on the leaves are typical of spider mites.
Try this first (free)
- Isolate the plant so the pests don’t spread.
- Rinse the leaves, tops and undersides, with a gentle spray of water.
- Check the undersides of the leaves every few days.
If that’s not enough
Oils and soaps work physically on soft-bodied pests, and UConn notes that makes resistance unlikely (UConn IPM). Lost Coast Plant Therapy is labeled for all mites and is the first spray we reach for (Lost Coast Plant Therapy, Lost Coast Plant Therapy). Lost Coast on Amazon →
Read more: indoor herb pest control
Likely cause
Aphids
Clusters on soft new growth and sticky leaves are the usual signs of aphids.
Try this first (free)
- Isolate the plant so the pests don’t spread.
- Rinse the leaves, tops and undersides, with a gentle spray of water.
- Check the undersides of the leaves every few days.
If that’s not enough
Lost Coast Plant Therapy is labeled for aphids and, the maker says, can be used up to the day of harvest (Lost Coast Plant Therapy). Lost Coast on Amazon →
Read more: indoor herb pest control
Likely cause
Whiteflies
A cloud of tiny white insects that lifts off when you brush the plant.
Try this first (free)
- Isolate the plant so the pests don’t spread.
- Rinse the leaves, tops and undersides, with a gentle spray of water.
- Check the undersides of the leaves every few days.
- Yellow sticky cards near the plant catch adults.
If that’s not enough
Lost Coast Plant Therapy’s label covers whiteflies (Lost Coast Plant Therapy). Spray in low light and let the leaves dry before the grow light comes back on. Lost Coast on Amazon →
Read more: indoor herb pest control
Likely cause
Powdery mildew
A white, powdery coating on the leaves.
Try this first (free)
- Pinch off the worst leaves and throw them away.
- Give the plant a little more space and air around it.
If that’s not enough
Lost Coast Plant Therapy is labeled for powdery mildew as well as pests, and it’s plant-based: soybean oil, peppermint oil and citric acid (Lost Coast Plant Therapy). Lost Coast on Amazon →
Read more: our Lost Coast spotlight
Likely cause
Cold damage
Basil especially dislikes cold, and a windowsill can get much colder than the room at night.
Try this first (free)
- Pull pots back from the glass on cold evenings.
- Keep herbs away from drafty doors and vents.
- Snip off badly damaged leaves once new growth starts.
Read more: why indoor basil dies
Likely cause
Flowering (bolting)
Herbs taste best before they flower. For annual herbs grown for leaves, removing flower buds encourages more leaf growth (Iowa State Extension).
Try this first (free)
- Pinch off flower buds as soon as you see them.
- Harvest from the top, just above a leaf pair, to keep the plant bushy.
If that’s not enough
Annuals like basil flower and decline eventually even indoors (UMN Extension). After several harvests, Iowa State suggests starting new plants from seed (Iowa State Extension). Our Botanical Interests and SeedsNow spotlights cover seeds for a fresh start.
Read more: how to prune every indoor herb
Likely cause
Too many plants in one pot
A grocery-store basil pot is usually many seedlings packed together, competing for light and water.
Try this first (free)
- Tip it out and gently split the clump into 2–3 smaller clumps.
- Pot each one up in fresh mix and water it in.
- Give them your brightest window.
Read more: why indoor basil dies · how to grow basil indoors
Every diagnosis at a glance
Prefer to scan? Here’s the whole flowchart in one table. Tap a row to open that diagnosis.
| What you see | Likely cause |
|---|---|
| Tall, leggy stems | Not enough light |
| Pale, yellowing plant, soil dries normally | Low light |
| Yellow lower leaves, damp soil | Too much water |
| Drooping, dry soil | Thirsty |
| Wilting, mushy stems, wet soil | Root rot |
| Tiny dark flies around the soil | Fungus gnats |
| Webbing, speckled leaves | Spider mites |
| Clusters on new growth, sticky leaves | Aphids |
| White flies when brushed | Whiteflies |
| White powder on leaves | Powdery mildew |
| Dark spots after a cold night | Cold damage |
| Flowers, bitter leaves | Bolting |
| Grocery basil dying fast | Crowded pot |
Still stuck? Print the one-page Herb Rescue cheat sheet, follow the care calendar, or email us at [email protected] with a photo.
Sources
- Penn State Extension: growing herbs indoors
- Iowa State Extension: growing herbs indoors
- Iowa State Extension: growing, harvesting and drying herbs
- Iowa State Extension: providing more light for herbs indoors
- Mississippi State Extension: insect pests of houseplants
- University of Arizona Extension: houseplant insect reference
- UVM Extension: indoor herb pests
- UConn IPM: sticky cards fact sheet
- UConn IPM: managing insecticide resistance
- UMN Extension: growing basil
- Lost Coast Plant Therapy: FAQ
- Lost Coast Plant Therapy: ingredients
Frequently asked questions
Why are my indoor herbs dying?
Most indoor herb problems come down to light, water, cold or pests. Leggy, pale growth points to low light; yellow leaves with damp soil point to overwatering; tiny flies around the soil are fungus gnats.
Why are my herb leaves turning yellow?
If the soil stays damp a day after watering, it’s usually too much water or poor drainage. If the soil dries normally and the plant is pale overall, it’s usually too little light.
What are the tiny flies around my herbs?
Usually fungus gnats. Their larvae live in moist potting mix. Let the soil dry between waterings, lay yellow sticky cards flat on the soil, and use a BTi soil drench for heavy infestations.