Pepper Plant Leaves Turning Yellow? 8 Causes and Fixes

On this page

1. 1Why are my pepper leaves turning yellow?
2. 2Did the old leaves or the new leaves yellow first?
3. 3How do you tell the yellow patterns apart?
4. 4How do you fix a nitrogen shortage?
5. 5Is your soil pH behind the yellow?
6. 6Can overwatering turn pepper leaves yellow?
7. 7Are yellow leaves with brown spots bacterial leaf spot?
8. 8Could a virus be yellowing your plant?
9. 9Why do potted peppers turn yellow?
10. 10How do you take a soil sample for a yellowing plant?
11. 11How much do you feed a yellowing plant?
12. 12Why do pepper seedlings turn yellow or purple?
13. 13Will yellow pepper leaves turn green again?
14. 14Fixing yellow leaves, in order
15. 15Sources

Why are my pepper leaves turning yellow?

Look at where the yellow starts on your plant. On the lowest, oldest leaves first, it usually means your plant is short of nitrogen and is moving what it has to new growth¹. Yellow in other places, or with other signs, points to the soil pH, a pest or the roots.

Yellow pepper leaves: the pattern, the cause and the fix

Where the yellow shows	What else you see	Likely cause	Fix
Oldest, lowest leaves first, then upward12	Slow, weak growth, thin stems	Nitrogen shortage	Liquid fertilizer at the base of each plant or on the leaves
Between the veins of older leaves, veins stay green3	May go on to curling, dead spots and early leaf drop	Magnesium shortage	A soil test before you add anything
Between the veins of new leaves, veins stay green24	Often on soil above pH 7.0	Iron held back by high pH	Test the pH; a foliar spray of ferrous sulfate or chelated iron corrects it
Fine yellow dots, leaves may look bronzed5	Webbing, tiny moving dots under the leaves	Spider mites	Strong water jet; insecticidal soap if they persist
Yellow and distorted leaves5	Soft insects and sticky honeydew underneath	Heavy aphid infestation	Water jet, insecticidal soap or neem or canola oil
Yellowing foliage with the upper leaves wilting56	Red-brown streaks inside the stem	Fusarium wilt, favored by wet soil	Well-drained soil, no waterlogging; rotate and choose resistant varieties
Light green, mottled, curled leaves6	Stunted plant, misshapen fruit	Virus	Pull the plant; control aphids and weeds
Yellow leaves on a plant that has stopped growing6	Stunted growth	Curly top virus or a wilt disease	No cure: pull the plant; set out a few spares next year

Read the pattern before you feed: fertilizer fixes only the first row, and too much of it brings on the aphids in the fifth. UF/IFAS notes that too much nitrogen makes plants more inviting to aphids and whiteflies⁷.

Did the old leaves or the new leaves yellow first?

That one question splits the nutrient causes in half for you. Nitrogen and magnesium move inside the plant, so a short plant pulls them out of its old leaves to feed the new ones, and the old leaves yellow first¹³. Iron stays put, so its shortage shows on the young leaves³.

Yellow pepper leavesFind the first leaves that changed

• Oldest, lowest leaves firstNutrients that move to new growth
  • Even yellow, veins and allNitrogen shortage (Iowa State)
  • Yellow between green veinsMagnesium shortage (Iowa State)
  • Yellow and scorch along the edgesPotassium shortage (Iowa State)
• Newest leaves firstNutrients that stay put
  • Yellow between green veinsIron held back by soil above pH 7.0 (UMD)

^{3 sources}Sources for this line1. Iowa State University Extension and Outreach, Yard and Garden2. University of Maryland Extension3. Iowa State University Extension and Outreach, Yard and Garden

So two of your leaves with the same green-veined pattern can mean two different things. On your oldest leaves it points to magnesium; on the tip leaves, to iron and a high pH. Yellow that starts at the edges of your old leaves, with a scorched brown rim, fits potassium instead³; that one, too, calls for a soil test rather than a guess at the garden center. Iowa State also warns that the tissue between the veins can brown fast with magnesium shortage, often within about a day³, so look again tomorrow if you are unsure.

How do you tell the yellow patterns apart?

Hold one of your yellow leaves up to the light and look at the veins. A nitrogen-short leaf fades evenly, veins and all, while iron chlorosis leaves the tissue beside the veins green². Mite damage looks different again: fine yellow stippling rather than a solid color⁵.

1Even yellow from the oldest leaves up: nitrogen¹2Yellow between green veins: iron, often from pH above 7.0²3Yellow stippling and webbing: spider mites⁵

1. Even yellow from the oldest leaves up: nitrogen¹
2. Yellow between green veins: iron, often from pH above 7.0²
3. Yellow stippling and webbing: spider mites⁵

Spider mites hide until the damage shows. Penn State says you usually notice them only once the leaves show damage, that they thrive in dusty conditions and they hit water-stressed plants harder⁵. A sheet of white paper held under a branch while you tap it shows you the moving dots.

Pepper Geek walks through six reasons pepper leaves turn yellow and how to fix each, a handy second view of the patterns in the table above.

How do you fix a nitrogen shortage?

Feed your plant, lightly, and only once you have ruled out pests and wet roots. UMD Extension says to apply a liquid fertilizer at the base of each plant or on the foliage when you see deficiency signs, and to test the soil pH and nutrients every three years². UMD adds that nitrogen in particular may run short early in the growing season.

Time a leaf spray well. UMD says the best time for a foliar feed is early morning or early evening, when the leaf pores stand open², so you skip the midday sun.

Stop once the new growth comes in green. Too much nitrogen gives you a bushy, leafy plant that is slow to bear⁹; the pepper fertilizer guide has the side-dress amounts and timing. Iowa State notes that a long or severe shortage leads to leaf drop and lower yields¹, so a light feed now beats a heavy one in August.

Is your soil pH behind the yellow?

Often, when the leaf veins on your plant stay green. UMD calls pH 6.5 ideal for vegetables and says plants still produce from 6.0 to 7.0²; UC IPM keeps pepper soil at 6.0 to 6.5¹⁰. Above 7.0, iron gets locked up and the new leaves yellow between their veins².

For iron chlorosis, extra nitrogen will not help you. UF/IFAS corrects the yellowing with a foliar spray of ferrous sulfate or EDDHA-chelated iron⁴, and on naturally alkaline soil recommends a fertilizer with micronutrients⁷. To bring pH down over the longer run, UF/IFAS uses about 1 pound of sulfur per 100 square feet for one pH point⁷, but your soil test report sets the amount.

Magnesium has no fix in the sources we read for this guide. Iowa State describes the signs but gives no treatment, so a soil test that measures magnesium is your next step before you add Epsom salt or anything else³.

Can overwatering turn pepper leaves yellow?

Yes, in two ways: through roots that run short of air, and through the root diseases that wet soil invites. Utah State's overwatering guide lists leaf yellowing, wilting and leaf loss among the signs of saturated soil, which pushes the air out and kills roots¹¹. Utah State's own answer to yellow, stunted pepper plants names wilt disease and says to avoid overwatering to prevent it⁶.

Neither has a spray fix in these guides, so your work goes into the soil. Dig up a wilted plant and look at the roots: UC IPM describes rapid wilting above roots gone dark brown and water-soaked¹². The prevention is the same for both: water deeply and less often, 1 to 2 inches a week in the ground, and let the soil drain between soaks, as the guide to watering peppers lays out⁶.

Are yellow leaves with brown spots bacterial leaf spot?

If your leaves have small brown spots with a yellow edge, check for bacterial spot before you feed. UF/IFAS says the first signs are water-soaked spots on the underside of the leaf, within 3 to 4 days of infection, with a dark-green halo around a tan lesion¹³. The spots then join up into large patches of yellow and brown tissue, and your leaves often drop early even when the damage looks moderate¹³.

Water carries the bacteria from plant to plant, in rain, heavy dew and splashes, and the pathogen can also arrive on seed, so you can bring it home in a nursery tray¹³. You cannot cure the disease with a spray at home, and you may not need to try. UF/IFAS says copper bactericides have limited effect because many strains tolerate copper, and it points you to resistant varieties, crop rotation and staying out of the planting while the foliage is wet¹³. Water at the base, and pick or tie your plants only after the leaves dry.

Could a virus be yellowing your plant?

If your plant has stopped growing, yes. Utah State's answer to yellowing leaves with stunted growth names curly top virus or a wilt disease, says to destroy infected plants, and suggests you set out a few extra plants to cover the losses⁶.

Insects carry these viruses from plant to plant, so knowing the carriers tells you what to watch. New Mexico State names three groups for the pepper viruses common there¹⁴:

• Leafhoppers, including the beet leafhopper that carries curly top.
• Thrips, which spread tomato spotted wilt.
• Aphids, which spread alfalfa mosaic and pepper mottle.

For curly top, New Mexico State covers young pepper plants with row covers early in the season to keep the beet leafhopper off¹⁵. Utah State adds the habits that slow every virus: control aphids, pull nearby weeds, and avoid tobacco products while you handle the plants⁶.

Why do potted peppers turn yellow?

Usually because the pot ran out of food or stayed wet. Potting mix holds little fertilizer, so UW–Madison adds a slow-release fertilizer if your mix has none and follows the label from there¹⁶. Once a big plant carries fruit in summer heat, it needs water daily¹⁶, and every soaking that runs out of the drainage hole carries some of the feed with it.

A wet pot yellows for the opposite reason. UW–Madison wants a drainage hole and mix all the way to the bottom, because a layer of rocks slows drainage¹⁶. If your pot stays heavy and wet for days, fix the drainage before you add a feed, or the roots cannot take it up.

How do you take a soil sample for a yellowing plant?

Five minutes of digging gets you a pH and nutrient report that settles most of your guesses above. Colorado State's soil lab gives the steps for a vegetable bed: take 10 to 15 small samples from the surface down to 6 or 8 inches, mix them in a clean bucket, and send about 1 pound of the mixed soil¹⁷.

1. 1

   Pick the area

   Send a separate sample for any part of your garden with a different crop history, soil color or fertilizer history.¹⁷

2. 2

   Dig 10 to 15 small samples

   Use a stainless steel trowel, spade or probe, and go 6 to 8 inches deep. Clear away litter such as crop residue, grass and wood chips first.¹⁷

3. 3

   Mix them in a clean bucket

   Break up the clumps and stir your samples into one composite.¹⁷

4. 4

   Bag about 1 pound and label it

   Write your name, the depth and a sample name on the bag, and match the name on the submission form.¹⁷

Ask the lab for pH, nitrogen, magnesium and iron if it offers them, and check your own state's extension lab for its forms and fees. The same page recommends sampling in early spring before planting or fertilizing¹⁷, so you can take a sample now to diagnose a sick plant and another in spring to plan next year. Compare your report with the pH range in the section above before you buy any amendment.

How much do you feed a yellowing plant?

Less than the yellow tempts you to give. Utah State side-dresses each plant with just 1/4 tablespoon of 21-0-0, placed 6 inches from the stem and watered in⁶. For a row of six plants that is 1 1/2 tablespoons in total, about one heaped spoonful.

A liquid feed works faster for a plant that already shows the yellow, which is why UMD uses one at the base of each plant or on the leaves². Mix it to the label, give it once, and wait a week or two for green new growth before you give another. Extra nitrogen brings the aphids from row five of the table⁷, so a second heavy feed swaps one problem for another.

Why do pepper seedlings turn yellow or purple?

Usually cold soil, while your seedlings are still young. UMD Extension says seedlings and transplants often run short of nutrients in early spring because their roots are small and cool soil slows the release of nutrients². It recommends a balanced soluble fertilizer at the base of each plant or sprayed on the leaves, mixed to the label.

Purple is the phosphorus version of the same problem you may see in spring. UMD sees purple leaves on young plants in cold spring soil and uses a starter fertilizer, which carries a higher share of phosphorus, at planting². Your seedlings usually green up once the soil warms and the roots spread, so wait for soil of at least 60°F before you plant them out. Penn State germinates pepper seed at a soil temperature of 70 to 85°F⁵, so if your tray sits on a cold windowsill, you can warm it before you feed it.

Will yellow pepper leaves turn green again?

Do not judge your fix by your old leaves. None of the extension pages read for this guide says a yellow leaf greens up again, so watch the new growth at the tips instead.

• New leaves come in green after a feed. The fix worked. Stop feeding nitrogen and let the plant carry on; the yellow bottom leaves may drop on their own, as Iowa State expects with a long shortage¹.
• New leaves come in yellow between green veins. Your feed did not reach the problem. Test the pH, because iron held back by soil above 7.0 needs a different fix².
• The whole plant keeps yellowing and wilting. Look at the roots and the stem. Red-brown streaks inside the stem or dark, soft roots point to a wilt or root rot⁵¹², and no feed fixes those.

You can pick off badly yellowed leaves that touch the soil; it tidies the plant and costs it little. If the leaves are also curling, the pests and viruses in the guide to curling pepper leaves may be the cause.

Fixing yellow leaves, in order

Work down this list; each check costs you less than the next.

Give each step a week or two before you move to the next one, and watch the newest leaves at the top of your plant. They show you first whether the change worked.