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Tip #3: Caring for Your Potted Peppers

 

Direct Sunlight and Temperature

Give your potted peppers as much direct sunlight as possible—at least 7 hours each day. With days growing shorter, they’ll need every minute of strong sunlight to grow and to maintain the foliage they have.

Indoor sun is much weaker than outdoor sun because glass reflects and absorbs much of the sun’s energy. Also, light comes from only one direction—through the window—in most homes, so plants can’t benefit from light coming from other angles or bouncing off clouds.

When nighttime temperatures consistently drop below 50-55°F, bring your plants indoors. For peppers that aren’t as robust as you’d like them to be, keep them above 65°. The next morning, after the sun raises the air temperature, move the plants outside until the temperature drops again. On cold days, of course, the plants will need to stay indoors.

Setting an alarm will remind you to bring the plants indoors. You know what will happen if you forget!

Direct sunlight provides the energy that drives photosynthesis. The more sun the plant gets, the more glucose it can make in its leaves. Glucose fuels all cellular activities, including root and foliage growth, flower and fruit formation, and making hormones and enzymes.

 

 

For ease of transport, I keep all potted peppers in large plastic bins. On a sunny morning, the bins go out to the enclosed porch, where the peppers bask in the sunshine and warmth (peppers are at the top of the photo, above). Peppers come back indoors for the night when the temperature drops below 50°. Avoid keeping them near heat registers, where the air is very dry.

At the time of this writing—mid-October—in USDA zone 7b, our average nighttime temperatures are around 50°F, but that’s just an average. This week, the weather forecast is calling for temperatures 10+ degrees lower than that, so I’ve brought in all the basil, peppers, and other tropical plants that need warmer conditions.

Artificial Light

Adding supplemental light can make the difference between the plants thriving… and maybe not doing so well. The more light the plants get, the healthier they’ll be.

So, if you don’t have a protected outdoor space, a greenhouse, or a sunroom for the plants in the daytime and rely only on light coming through windows, you might need to supplement natural light with artificial light. A few lamps with LED bulbs or 2 shop lights (my preferred option) can work pretty well.

Place the plants very close to the source of light, but not so close that they can feel the warmth. Under 4′ long shop lights, each fitted with 2 “daylight” LED or fluorescent tubes, the tops of plants should be within a few inches of the tubes. Keep the lights on for 18 hours per day if they’re the main source of light. Very tall plants should be cut back to better accommodate them under the fixtures.

Direct sunlight is stronger than most sources of artificial light, although commercial greenhouse lighting systems rival natural sunlight. Artificial light is a must in long stretches of cloudy weather. It’s also helpful where daylength is very short for gardeners in the far north or at the southern extreme. What the lights can’t provide in intensity, they can make up for in duration. That explains the 18 hours. Run the lights longer if growth is weak. There is no substitute for light.

You might have noticed my repeated emphasis on providing strong light for your potted peppers. In all the years I’ve grown peppers indoors and from customers’ comments, lack of adequate light is the #1 reason for failing with any sun-loving plant.

 

Water for Potted Peppers

 

 

 

Potted peppers should be kept lightly moist, never wet. Because they’re growing in fairly large pots, the soil in the lower 3/4 of the pot might have enough moisture even though the topsoil feels dry. Stick your finger 2″ into the soil; if there’s any dampness, don’t water yet.

When you’ve grown potted plants for a while, you’ll recognize the need for water by the weight of the pot.

If the plant is not wilting and skies are cloudy, delay watering. I prefer to water most plants on sunny mornings and when the forecast calls for two or more days of sunny weather. In sunny conditions, plants photosynthesize, transpire, and respire at an accelerated rate. Consequently, they use that water faster, so it’s less likely to damage roots. However, if the plant is beginning to wilt due to dry soil and the weather is cloudy, give it some water, but not a thorough watering.

Never let excess water collect in a saucer; remove it within 15 minutes. Give this water, which has dissolved nutrients, to other plants. Avoid sending that excess water (leachate) down the drain or into the creek. Surface runoff pollutes large bodies of water, creating algal blooms and killing aquatic animals.

Normally, we water fully rooted plants thoroughly, until it begins to drain through the holes. If water rushes through the soil and exits immediately through the drainage holes, there’s probably an air gap between the pot and the outside of the root ball. Firm the soil or use a chop stick or a wooden dowel to force soil into the gap. You might need to pack the soil more firmly when potting up.

In cool weather, use lukewarm water—about 85°F—to avoid shocking the plants. Because I keep my house cooler at night in winter (58-60°), peppers, basil, and other tropicals enjoy lightly warmed water. I’ll even go as far as keeping small potted basil plants on top of the 78° aquarium for the night, then returning them to the sunny window in the morning.

 

Fertilizer

 

 

Roots of plants growing in the garden can explore quite a distance from the stem for the nutrients they need. In a pot, however, roots are restricted to what’s available in the potting soil. Therefore, we need to provide small amounts of fertilizer as growth warrants. Most plants thrive when quite potbound as long as they have the moisture and nutrients they need.

When my plants continue producing a few peppers during winter months, I give them diluted concentrations of fertilizer, maybe 1/4 or 1/2 strength every 4-6 weeks. Less fertilizer is better than too much. So, if you’re in doubt, don’t fertilize. Use formulations with relatively small numbers, such as 5-10-10 or 14-14-14. Like their cousins, the tomatoes, peppers need calcium to prevent blossom end rot.

An oversupply of nutrient salts in the soil draws water out of the roots, causing a condition frequently referred to as “burning the roots”. Overfertilized plants soon wilt and most die. If you think you’ve applied too much fertilizer, flush 1-2 gallons of clear water through the soil. Collect the leachate, add more water, and use it on plants in the garden.

“Do peppers need fertilizer?”

Plants that look healthy but are not flowering don’t necessarily need fertilizer. They might simply be in a state of semi-dormancy from late December through January, when not much growth occurs other than maintenance of plant tissues.

 

 

If plants stop growing leaves or turn pale green, they might need nutrients. Nitrogen is a macronutrient, needed in large amounts compared to other nutrients. Nitrogen helps the plant grow chloroplasts and new foliage, keeping it a healthy green color. When plants are young, use products with higher nitrogen (N) levels. Once they approach the flowering stage, use less N and more phosphorus (P) and potassium (K). All fertilizer labels include 3 numbers, such as 21-8-14, representing 21% nitrogen—8% phosphorus (phosphate)—and 14% potassium (potash), always in that order.

There are literally thousands of molecular activities going on inside plant cells, and each nutrient plays an important part in many of them. Surprisingly, plants need only 16-20 elements, so skip the products that advertise they contain half the periodic table.

Avoid fertilizing plants if the soil is very dry. Water, and then fertilize a day or two later. Some nutrients in a fertilizer solution can be absorbed when sprayed on the foliage. Wait several weeks after potting up to begin fertilizing peppers, and fertilize less often in winter.

Timed Release Fertilizer

Another option is to add timed release fertilizer when potting up the plants. Some products last 3 months while others last 6-8 months. Apply an amount described on the container as a moderate rate. I add them about an inch below the soil surface so they won’t spill out, wash away, or release nutrients faster in the hot sun.

Nutrients inside the little prills release faster at temperatures above 70°, so you might need to reapply or use a different fertilizer before those 3 or 6 months have passed.

During the main growing season, in summer, I usually use timed release fertilizer in smaller amounts and supplement with liquid or granular organic products.

“Should I use organic fertilizer?”

For greens and vegetables in containers and for those growing in my gardens, I use organic products most of the time. Fish emulsion, SeaPlus, compost, aged cow manure, blood meal, earthworm castings, the Espoma brand of fertilizers, and others provide nutrients and help sustain the plants and populations of microbes.

Living microbes consume and break down organic matter in the soil, releasing simpler nutrients when they die. This natural process happens continuously in all healthy soils, except when they’re very cold.

Some gardeners prefer the chemical (or synthetic) fertilizer products. In my opinion, using them does not make produce toxic since organics and synthetics break down to similar compounds. The plant reconfigures those nutrients into useful substances needed for normal growth.

Organics, however, add microbes and enzymes, increase crop yields, and provide some protection from harmful microorganisms. They improve the quality of the soil for long-term production. Organic fertilizers have low numbers on the package, such as 3-5-4 or 5-1-1, but they release nutrients over a longer period of time.

Regular use of chemical fertilizers harms populations of microbes and earthworms. Incidentally, since microbes are dead or dormant in cold soil, I use synthetic fertilizer once or twice in cold weather. This maintains vigor for the hardy greens growing through the winter in outdoor gardens. But for potted peppers, I use organic products to supplement their nutritional needs.

 

Insects and Spider Mites

Many plants serve as hosts for hungry aphids and spider mites. You might also occasionally see caterpillars, found on partially eaten leaves. I pick the small caterpillars and feed them to my 40-year-old salamander; larger caterpillars go to the birds outside.

Spider mites cause tiny light-colored dots on the leaf surface as they feed from and kill those cells. Their populations can build up very fast in warm temperatures, when you’ll see fine webbing and dusty debris on the leaves.

In this photo of Alocasia, a tropical houseplant, you can see the tiny spots caused by spider mites. The damage looks similar on pepper plants.

Outdoors, wind, rain, and predatory insects keep populations of spider mites in check. But in the protected indoor environment, we need to keep a watchful eye. Fortunately, spider mites drown easily, so a heavy misting or a brisk rinse under the garden hose kills most of them. Do this on a warm day. Test the temperature of the water coming out of a hose sitting in the sun; it might be too hot.

If the mites persist, use a dilute solution of horticultural oil—not neem, dormant, baby, or vegetable oil. I use SunSpray Ultra Fine Horticultural Oil, sprayed on all surfaces to smother and kill mites and their eggs. This product is safe to use on edibles. But be careful; it makes surfaces slippery. Read the label.

Aphid populations also build rapidly in warm temperatures. They reproduce by giving birth to live young. At certain times of the year, they mate and produce eggs, but we deal primarily with live bearers. A vigorous spray from the garden hose and horticultural oil work against aphids, as well.

Aphids and several other insects excrete “honeydew”, derived from the glucose-rich sap the aphids feed on. This substance (the insects’ excrement) appears as a clear and sticky layer on foliage beneath where the aphids are feeding. Eventually, black sooty mold colonizes the honeydew, shading the leaves and causing them to turn yellow.

You might not see these pests for the first month or two your potted peppers are living indoors. But after enjoying your warm hospitality, they could show up. Scout for them regularly, and treat the plants right away.

The Tobacco Hornworm

This section added 6/16/2025.

 

 

***Update***: On the few remaining peppers potted up last year, I noticed the tell-tale droppings and missing foliage caused by a tobacco hornworm. But the insect was so well camouflaged that it couldn’t be found. I sprayed the peppers with Btk, an organic biological insecticide, a couple of hours before it began to rain. Later, I saw one small dead caterpillar hanging from a branch. I placed it near the bird feeder. Btk (Bacillus thuringiensis v. kurstaki) is safe to use on edible plants and targets only larval moths and butterflies—in other words, their caterpillars.

Tobacco and tomato hornworms don’t pester our plants in large numbers, but these 4″-long caterpillars can do some damage! They attack tomatoes, peppers, and a few other crops. The adult is one of the large hawkmoths.

Beneficial Insects

If I see ladybugs hanging around the warm porch, I place them on a pepper plant with aphids. The ladybugs go to work immediately, helping rid the plant of aphids.

Another beneficial insect is the tiny non-stinging braconid wasp. Thousands of braconid wasp species work around the globe, unseen and underappreciated. Each species targets a particular species of aphid, caterpillar, or other insect pest.

The “white rice” on the hornworm (photo, above) are pupating braconid wasps. A female wasp lays eggs on or in the growing caterpillar. Those eggs hatch and feed on the caterpillar’s interior tissues, weakening the host. With enough larvae, the caterpillar stops feeding and dies. (I leave that one alone.) The larvae pupate before hatching out as adults, which then hunt down other caterpillars to parasitize.

 

 

Not using pesticides in the garden allows the ecosystem to develop an efficient system of predator and prey.

 

 

Headings

Page 1: As Autumn Approaches (Why would we grow potted peppers in winter?, Early Fruits Next Summer), Tip #1: Start with Healthy Transplants, Tip #2: Transplanting Potted Peppers (The Pots, The Potting Soil, The Process, The First Watering, Varieties of Potted Peppers Often Grown Indoors, Dig It)

Page 2: Tip #3: Caring for Your Potted Peppers (Direct Sunlight and Temperature, Artificial Light, Water for Potted Peppers, Fertilizer, Timed Release Fertilizer, “Should I use organic fertilizer?”, Insects and Spider Mites, The Tobacco Hornworm, Beneficial Insects)

Page 3: Tip #4: Pollinating Your Potted Peppers, Tip #5: Fruits from Your Potted Peppers (No New Fruits?)

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