Planting too early
For a general rule, wait until night temperatures are above 55°. Habaneros, super hot pepper plants, and eggplants prefer 60°, and tomato plants can handle 50°, but we recommend keeping it simple and only learning one number which is 55°.
Planting early where there's more likely to be cool, wet conditions can stress young plants, which makes them more suseptible to disease.
A plant suffering chill damage may get stunted, which is where the plant doesn't die, but it also doesn't grow. It will pull out of a stunted condition with warm days and nights, and fertilizer.
To get a jump start on your season, up pot your plant into a slightly larger container. Keep your plants in a sunny spot indoors, or move it outside during the day, and inside at night.
Inadequate Soil Preparation
Do not skimp on the organic materials! This doesn't mean certified organic per se. Organic material or organic matter in this sense means compost, shredded leaves, or animal manure.
Only mix into the soil if the material is broken down already. Otherwise add to the top of the soil as mulch, and it will fertilize the soil as it breaks down. If the material isn't broken down already, it will pull nitrogen from the soil away from your plants as it decomposes.
Don't mulch right up to the stem, and leave an open space around the stem. Mulching too close to the stem will trap moisture around the stem, which will make it suseptable to disease.
For existing gardens, do not plant peppers, tomatoes, or eggplants in the same spot more than once every 3 years. This decreases the chance of your plants becoming susceptible to disease. If planting in the same location every year, adding a very large amount of organic matter to the soil at the end of the season will help stave off disease problems.
Too Much Water
Most plant problems are due to over-watering, allow the soil to dry before watering. Feel the soil a few inches down to check for moisture, it's ok if the top surface of the soil is dry. Make sure this is below the soil line - if your mulch is 3" deep, you'll want to check 6" down from the top surface.
If your pepper plant looks wilted with drooping leaves (flagging) during the day, this does not necessarily mean the plant is in need of water. If it hot and dry outside, the plant will transpire more moisture than it can take up from the roots. It is possible for the pepper plant to flag while having plenty of available water, especially while the root system is small and can't access all available water in the soil. If your plant is flagging in the morning, then it definitely needs water.
The morning is the best time to water your plants. Water deeply at the base of the plant and try not to get water on the leaves. If your plant is in a container, water until it flows out of the bottom. Watering in the morning allows the plant to have more available water during the heat of the day, and also for water on the leaves to evaporate. Water that remains on the leaves is a vector for disease. That is what makes night watering risky, because the water will stay on the leaves with cooler temperatures.
Roots need water of course, but they also need air! Too much water will block out access to air.
Inadequte Fertilization
Plants use up nutrients in the soil when they grow, and if those nutrients aren't replenished each year, or often enough during the season, your plants will not grow or produce to their full potential. Of course we recommend the fertilizers we have for sale (they're what we use at the nursery), but any high quality fertilizer is likely to be effective. It's unlikely that you'll find a high quality fertilizer at a big box store, so search out your local garden centers or order online. A little goes a long way, so it's well worth it to invest in high quality fertilizer.
