Look at the seeds and you will see that pepper and eggplant are quite similar to tomato seeds. This is because they are all members of the classification family, Solanaceae. Tomatoes are Solanum lycopersicum, peppers are Solanum capsicum, eggplants are Solanum melongena, tomatillos and ground cherries are Solanum physalis, potatoes are Solanum tuberosum and tobacco is Solanum nicotiana.
Tomato, eggplant and tomatillo germination temperature is around 80 degrees and take less than 14 days, but peppers need around 90 degrees ad can take up to 21 days. They will germinate at lower temperatures, but germination rates might be lower and take longer.
The information here will mostly be about peppers. Here’s the thing with peppers: Unlike the others, they include several species. Referring to capsicums as “hot” or “sweet” is a culinary classification, not a scientific one.
C. annuum are actually not annuals, but perennial where temperatures remain between 60F and 85F. This is the most widely cultivated species and offer the greatest number of varieties, including bells, Cayenne, Poblano, Serrano and Jalapeño.
C. chinense grow best in areas of high heat and humidity. These include the hottest peppers, like Carolina Reaper, Habanero, Scotch Bonnet and Bhut Jolokia. They are finicky and need longer growing seasons. Seeds take longer to germinate and fruits take longer to mature.
C. frutescens love sun, heat and humidity, but do not tolerate drought well. This species includes Tabasco and Thai bird chilies.
C. baccatum is more challenging to grow. Plants are lanky and fruit takes a long time to ripen. They must have full sun all day, warm soil, but not too much water. Aji Amarillo and Lemon Drop are varieties you might have heard of.
C. pubescens are the most difficult to grow. Native to the cool Andes; they are more cold-tolerant, require plenty of sunlight, but may not do well in high temperatures, preferring 40-70° F. They take longer to grow to full size plants and mature fruit. An example of C. pubescens is the Manzano (“apple” in Spanish). It is shaped like a golf ball-sized apple. Citrusy sweetness, paired with the pepper’s thick walls, make the Manzano taste like a richer, spicier, tastier mini bell.
Most of us plant peppers outdoors when we plant our tomatoes. However, they should only be grown outdoors when night temperatures are consistently in the 60s.
Seed Starting
Solanums really want sun and wind, they are not indoor plants. In the average home, even with lights, heat mats and fans, seedlings won’t stay healthy for long. Start them too early and you will be giving them more time to grow pale and skinny or die of disease.
Moist planting medium: The first thing to do is moisten (moist, not wet) your planting medium. I keep the bulk of it dry, so it doesn’t get moldy. I like a gallon bucket with lid and moisten only the amount I plan to use. If you do this a few hours before, it gives the water time to soak in and you can later add more water or mix, depending on how moist you want it to be.
Label, label, label. Seedlings of each species all look the same. Make your labels before you even open the seed packet. Stick the label into the mix before you plant, to avoid disturbing the newly planted seed.
Planting depth is usually indicated at ⅛ to ¼ inch. Either fill the mix and poke holes the right depth or place the seeds and top up the mix over it. Better too shallow than too deep. Gently tamp down the surface to have the seed make good contact with the moist mix. Do not water, or the seed will move all over and even float to the surface. Bottom water until roots can hold it in place.
Heat and humidity: It’s possible to get germination in 5 days. I pick the coldest nights and place it on a table, over a radiator. You don’t want them to cook, just to hang out in a steam room. Or you could use a heat mat, like a sane person. I try to avoid the extra carbon footprint and electricity bill.
Water sparingly, after leaves start to appear and keep them warm. Leave them on a heat mat. They need more heat than tomatoes and are not as tough. Cool, wet soil may cause rot.
Transplant seedlings when they have two pairs of leaves. If you have a few growing together, they tease apart easily, especially if the planting mix was not compressed. A toothpick helps, so you don’t squeeze and pull too hard on the stems. Hold the leaves or stems very gently to avoid bruising. Transplant each into a pot at least 3 inches deep. Fill it up to the brim, make a hole all the way to the bottom, then ease the seedling in until only one pair of leaves remain above soil level. These are not tomatoes, they do not root from all along the stem, so avoid planting them too deep; ¼ – ½ inch above the root level will do nicely. Gently press the mix down to secure the seedling in place and water it in.
Hardening off is the process of acclimatizing them to the outdoors. Toughen them up by putting them outdoors for a few hours a day. They need to adjust to the intensity of the sun and the drying effects of wind. Too much, too soon, and they can scald and dry out. A bit like a person starting a tan.
Most solanum growers will experience some setbacks or disappointment. Just enjoy the ones that do make it and learn from your experience.