What to do now
Mildest step first.
- Check where the white is: patches only on the surfaces the sun hit point to sunscald, while damage after a cold night or on the newest growth points to something else.
- Shade the plants for the next few days with a basket, an upturned pot during the brightest hours, or floating row cover.
- Keep the soil evenly moist while new leaves grow in; the white patches won't recover, but the plant usually does.
- Harden off the rest of your seedlings for 7 to 10 days before they go out.
Is it sunscald?
When transplants turn white soon after planting, the most common cause is sunscald, also called sunburn. University of Maryland Extension describes it as parts of the leaf turning papery white or tan, only where the leaf had direct sun for an extended time. A note in the University of Delaware's Weekly Crop Update adds that the tissue right next to the scalded area is still bright green. The University of Minnesota notes that young stems of transplants can also turn white, on the exposed side only. The pattern is the clue: the damage follows the sun, so leaves that were shaded by other leaves stay green.
Why it happens
Seedlings raised indoors or in a greenhouse have only had filtered light. Nebraska Extension notes that outdoor sun is often more intense than light from grow lights or a greenhouse, and that it can sunburn the leaves of plants that were not hardened off. Hardening off, University of Delaware explains, lets plants build up the waxy cuticle on their leaves and adjust to brighter light. Maryland puts it plainly: hardening off would have prevented the sunscald on new transplants. Established plants can scald too, during a heat wave of three or more days at 90°F or above, but on new transplants the usual story is a bright day right after the move.
Will the plant recover?
Usually, yes. The white tissue is dead and won't turn green again. University of Maryland's advice is to support the plant with steady water and feeding until it grows new leaves. UNH Extension, answering a gardener with sunburned seedlings, said the new leaves will probably grow in fine, and to worry more if plants go droopy and don't stand back up. Delaware suggests watching the damaged leaves for leaf diseases that can get into the dead tissue.
The first few days
For the first few days after planting, University of Maryland suggests protecting transplants from wind and direct sun with baskets, flower pots or , and planting on a cloudy, calm day. Sources differ on the time of day: Utah State suggests morning or a cloudy day, while University of Vermont Master Gardeners suggest evening, so plants get a cool night before their first full day of sun. Either way, the aim is to avoid setting plants out into a bright, hot afternoon.
Harden off the next batch
Hardening off takes about one to two weeks. Nebraska Extension suggests 7 to 10 days: start with 2 to 3 hours in a shaded spot out of strong wind, then add a few hours outside and a little more sun each day. Water a bit less often during that time, but don't let plants wilt. Estimates vary, from about a week (Delaware) to at least two weeks (Utah State), and Maryland gives 5 to 14 days depending on the crop. Maryland also advises bringing tomatoes and peppers in at night if it will drop below 50°F, and keeping tender seedlings in on windy days or when it is below 45°F.
Cold or wind?
If the pattern doesn't fit sunscald, think about the weather in the last day or two. Cold shows up right after a cold night. The University of Minnesota notes that cold injury happens below 50°F and that leaves look water-soaked and soft, then turn black, while University of Maryland shows frost leaving white to tan spots on tomato leaves; healthy plants usually outgrow it. Wind is the other common cause. Nebraska compares wind damage to sandblasting: leaf and stem cells are scratched, lose water and die.
Other look-alikes
A few other causes look similar. Scorched leaf edges after a strong starter solution or fertilizer point to salt injury, which Purdue notes can also kill roots; watering deeply to wash salts below the roots helps. White or pale new growth at the shoot tips, especially if weeds along the edge of the garden look bleached too, suggests herbicide drift. NC State notes that the new growth often comes back green within weeks, while the older white leaves stay white. Fine white speckling that spreads over time is more likely spider mites, which tend to be a hot, dry-weather problem rather than a planting-day one.
Read the whole label first: it must list your crop, and its directions (amount, timing, gear, bees, days before harvest) are the law. If this page and the label differ, follow the label.
- TomatoThe warm-season anchor of the summer garden.
- PepperA tropical perennial grown as an annual — patient, slow, and particular about warmth.
- EggplantA heat-demanding nightshade that needs more warmth than the tomato next to it.
- CucumberA thirsty vine that wants warm soil, steady water, and something to climb.
- ZucchiniThe summer squash that turns a garden into a produce stand — if you can keep the vine borers away.
- How do I harden off seedlings before transplanting?Gradually expose indoor seedlings to outdoor conditions over 7–10 days, starting with an hour of shade and building up to full sun and overnight temperatures before planting.
- My transplants look wilted and sad after planting — is this normal?Some wilting and leaf drop in the first few days after transplanting is normal; if a plant is still wilting after a week and well-watered, the roots may have been damaged.
- How cold is too cold to plant tomato transplants?Wait until nights stay above 50°F and the soil is about 60°F. Tomatoes survive cooler nights, but below 50°F they grow slowly and their flowers often fail to set fruit. A frost at 32°F can kill an unprotected plant. In many places that means about two weeks after the average last frost date.
- What are the white or tan papery patches appearing on my leaves during a heat wave?White or tan dry patches on the upper surface of sun-exposed leaves are heat scorch — the leaf tissue has been killed by a combination of excessive temperature and direct solar radiation.
- Why are the leaf edges on my plants crispy and brown after I fertilized?Crispy, scorched leaf margins after fertilizing are usually salt burn — excess fertilizer salts in the soil draw water out of root cells, essentially dehydrating the plant from the roots up.
- How do I overwinter pepper plants indoors?Peppers are perennials that frost kills, so a potted plant can be kept alive indoors until spring. Bring it in before nights drop into the low 50s°F, check it for pests, cut it back, and keep it cool, around 40 to 55°F, with a little light and very little water. Plan on a living plant in spring, not a winter crop.