In today’s Newsletter podcast, we revisit some advice given to us by America’s Favorite Retired College Horticulture Professor, Debbie Flower, on how to get your pepper seeds to germinate more quickly, which can take up to three weeks before you see green leaves popping up above the soil surface. We were talking to the Elk Grove Garden Club last month, a wide-ranging conversation, which included how to tell if those old vegetable or flower seeds you have tucked away in a drawer will germinate or not. You can hear the entire chat in Episode 253 of the Garden Basics with Farmer Fred podcast.
Home gardeners who grow their tomatoes from seed usually get fairly quick results after sowing the seeds indoors. Given the right germinating conditions - a soilless planting mix, good drainage, plenty of light, plenty of warmth - tomato seeds can pop up in 8-10 days.
Pepper seeds are a different story. Why is it some peppers can take weeks to germinate?
"The important thing in getting your (pepper) seeds to germinate is to keep them warm – the soil temperature should be in the 80's", says Renee Shepherd of Renee's Garden, a popular seed catalog based in Felton, California. "Germination is very much related to even moisture and warm temperatures. You should see germination within 2 to 3 weeks if it's warm enough. I strongly suggest using bottom heat to achieve the warmth the seeds need – most good nurseries carry good little electric seed starting mats which will keep your seeds at the right temperature to sprout. One online order source is Peaceful Valley Farm Supply."
For those who want to comparison shop, another source for heating mats for your pepper seeds: Amazon.
Another trick that some gardeners employ is soaking the pepper seed for a few hours before sowing to soften the seed coat. The value of that is open to debate.
"I have never heard of soaking pepper seed overnight and have never done it in 20 years of running a trial garden," says Shepherd.
On the other hand, Professor Debbie Flower, formerly of the American River College Horticulture Department, sees the benefits of some "immersion therapy" for pepper seeds. "We soaked our pepper seeds in hydrogen peroxide for 10 minutes," explains Flower. "That's not enough time to scarify (soften or break the seed coat), or even get them soaked, but enough to kill exterior diseases."
Many sweet pepper varieties will show their initial leaves about two weeks after planting the seeds. But some varieties of peppers take longer to pop up than others. "The hot pepper varieties take longer to germinate, some to three weeks," says Flower.
But if you are experimenting with the really hot pepper varieties, such as the Bhut Jolokia (Ghost Pepper), it could take up to four months, says the Trade Winds Fruit website:
"Chinense species (e.g. Habanero's) generally take longer to germinate than most common peppers. Keep soil warm to very warm (75-90F) for better germination. Do not use acidic soil. Some Chinense peppers, in particular Bhut Jolokia, Naga Morich and related peppers are very slow to germinate, averaging 1-4 months germination time."
By the way, if you are growing the Bhut Jolokia...you're playing with fire. The Ghost Pepper is rated at 850,000 Scoville units of heat. For comparison, the habanero rates 200,000; the Jalapeno is 5,000; the Anaheim equals 1,000. And sweet bell peppers? 0.
Another factor that can determine the rate of germination of pepper seeds: the pH of your seed starting mix. One of the most common ingredients in most seed starting mixes is peat moss, which is highly acidic, with a pH around 4.0. Pepper heads, including the Horticulture students at American River College, have found quicker germination when Coir (coconut fiber) is substituted for peat moss. Coir has a closer-to-neutral pH: around 6.5. The tests at American River College bear this out after trying Coir in their pepper seed soil mix. "We had the best germination of peppers ever!" says Flower.
And don't be in a rush to set them out in their permanent garden home. "Pepper seedlings need to be grown out until they have at least several sets of true leaves, and it is at least 55° at night before you plant them out," explains Renee Shepherd. "And they will need a little time to get used to being outdoors, as well."
In USDA Zone 9, that would be around mid-May. Be patient.
After originally talking about this speedy pepper germination technique, other gardeners chimed in with their favorite tricks. One method that was seconded by many: germinate your pepper seeds in between two moist paper towels in a room that is between 70 and 80 degrees. For many, that room might be the kitchen or bathroom. When the "tails" appear after about 6 or 7 days (the tails, by the way, are the emerging roots), gently transplant them into a moist, seed starting mix, preferably one that uses the more neutral coir instead of the lower pH peat moss. Or, make your own. My preferred home mix consists of equal parts coir, perlite and fine compost.
The improvements I would make to that germination suggestion? Use coffee filters instead of paper towels. That way, the emerging root doesn't get tangled, as happens when using fibrous paper towels. Pulling out germinated seeds from paper towels may be hazardous to their health.
Also, to insure a warm environment, here's something you could do in just about any indoor room: place the moist coffee filters, containing the pepper seeds, inside a glass baking pan. Place that on top of a germination mat. Cover the baking pan with plastic wrap to keep it warmer. I tried this at home, pepper seeds germinated with six days.
Thank you for also listening to the Garden Basics with Farmer Fred podcast! It’s available wherever you get your podcasts. Please share it with your garden friends.
Fred Hoffman is also a University of California Cooperative Extension Master Gardener in Sacramento County. And he likes to ride his bike.
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