My favorite thing to grow in my garden certainly has to be my hot peppers. Though you have to start the seeds earlier and wait for the harvest longer than anything else in your garden, your efforts can be rewarded with a bounty of hot peppers not available for purchase at any grocery store or even at all but the rarest of Farmer Market stands.
I love my wrinkly, warty, insanely hot ghost peppers, my mysteriously dark and dangerously fruity tasting chocolate habaneros, and of course the hottest pepper of them all the Carolina Reaper. There are so many exciting and unique hot peppers for you to grow, however this guide works just as well for more mainstream hot peppers like the classic habanero or Thai peppers.
Learning how to grow hot peppers in Wisconsin is not completely intuitive. These are typically a warm climate plant. Sure, Wisconsin summers can get hot and sticky, with highs pushing 100 degrees, but the warm weather season just isn’t long enough to have the success with hot peppers that you would achieve in the southern United States or the Caribbean. You have to help nature a bit and give the peppers a head start. This starts right away when you first plant the seeds.
When to Plant Hot Pepper Seeds in Wisconsin
Hot peppers need to be planted in March. I aim for around March 18th for my really hot peppers (habaneros or hotter) and March 25th for all the rest. However, I have planted my super hot pepper as early as March 1st without them getting too leggy. Though, I don’t recommend this unless you use a grow light.
I live in Appleton, WI which is growing zone 5a. If you live in a cooler part of Wisconsin you may want to err on the side of starting seeds up to a week later and if you live in a warmer area of Wisconsin you can get away with planting your seeds a few days earlier.
Ideal Soil Temperature for Germination
Hot peppers desire really warm temperatures for their seeds to germinate. Typically temperatures between 80-90 degrees are ideal. You can have success outside this range, but germination will be more sporadic and may take more time.
In order to achieve these germination temperatures in Wisconsin you are going to have to start your seeds indoors. Wisconsin has too short of a growing season to start these seeds outside after the weather warms up if you have any hope for a harvest before the fall frost.
However, even when starting your seeds indoors, it will still likely be a challenge getting ideal soil temperatures for your seeds. This is why I use and highly recommend a heat mat. These inexpensive mats are the perfect size for a seed starter tray and they have just enough power to heat up the soil in that tray to around 80 degrees. Using a heat mat will ensure you get optimum germination.
I also like using these seed starter trays not only because they perfectly fit my heat mats but also because they have a domed lid that fits on the tray. This lid helps trap heat and humidity inside the container essentially creating a mini-greenhouse for your pepper seeds. Once the seeds begin sprouting you will want to remove the lid to give them room to grow.
How to Care for Hot Pepper Seedlings Indoors
Once the seeds have germinated you now have hot pepper seedlings. Seedlings will tolerate cooler temperatures than seeds will. Therefore I will typically shut off my heat mat at this point and save the electricity. However I do still keep them inside this small greenhouse which warms up nicely as the sun hits it.
The seedlings need to be set in direct light, so a south facing window or porch door is ideal. Be sure to rotate them every couple of days if the plants are starting to lean. You want them to grow straight up, not sideways, otherwise they will get leggy. If your plants do accidentally get leggy you can bury them deeper so more of the stem is under soil and new roots will form.
How to Harden Hot Pepper Seedlings in Wisconsin
As the weather begins to warm up it is time to start thinking about moving your hot pepper seedlings outside. You can’t move them right into your garden or you will shock the plants and kill them. They need to be gently acclimated to the more variable weather and winds outdoors.
Early in May the weather is typically warm enough that plants can start spending time outdoors. Start by moving the pepper plants outside for just an hour or two at a time. Any longer can overly stress the plants and kill them. You will be able to tell if you are being too hard on the seedlings because they will lie down and feel limp. Each time you place the seedlings outside you can leave them out there a bit longer. This is called hardening. The stems become stronger and can tolerate the breeze more and they more easily withstand changes in temperatures.
After your pepper seedlings have been sufficiently hardened for about a week, you can start leaving them outside all day and night. However you still want to keep a close eye on the weather forecast and be sure to bring them indoors if there is a chance of frost.
When to Plant Hot Pepper Plants in Wisconsin
Finally, your months of dedication have paid off! Your seeds have germinated, seedlings grew, seedlings hardened, and are now ready to go into the ground! Hot pepper plants need to be planted after all risk of frost has passed. Forecast permitting, I typically plant my peppers outdoors around May 20th. However, it is not a bad idea to wait closer till June 1st so the soil can warm up more. Ideally the soil temperature during the day would be 75 degrees and 60 degrees at night. Laying black plastic trash bags over the soil will help it warm up earlier.
At this point you have successfully started a pepper plant in Wisconsin despite the shorter than needed growing season. The care needed for the pepper plant in the garden will be the same as any other region. In three months your efforts will be rewarded with some deliciously hot pods! Make hot sauce, salsa, or just try to eat one straight. It will be the crown jewel of your garden!
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