What is the fastest way to germinate pepper seeds? They do germinate a bit slower than other vegetables and that is especially true of hot peppers, so gardeners try all kinds of DIY solutions to speed up the process. In this post I will examine 10 popular ways to speed up the germination of pepper seeds and report on my own experiment that compares most of these methods.
Finally, a definitive answer to the question, what is the fastest way to germinate pepper seeds.
Germinating Pepper Seed Faster
Seed from sweet peppers germinates in about 1 to 3 weeks and those of hot peppers can take 4 to 6 weeks.
Almost all seed has some type of dormancy built into the genetics of the seed. In many cases it is a simple matter of having the seed absorb water and that is enough to trigger germination. Higher and lower temperatures can also affect the time it takes to germinate. And then there are seeds that require some kind of pretreatment before they germinate. Here are some commonly recommended methods.
- Soaking in water – this is required by all dried seed to start the germination process. Some people do this by planting in moist soil.
- Soaking in tea – various kinds of tea are claimed to work. The claim is that chemicals inside the tea speed up the process.
- Scarification – cutting or sanding of the seed coat, which then allows water to be absorbed quicker and makes it easier for the radical to exit.
- Soaking in hot water – the heat of the water can soften certain seed coats.
- Gibberellic acid (GA3) – affects hormone levels in the seed and can be used for slow germinating seeds.
- Freezing – does not normally work, but is suggested for pepper seed.
- Hydrogen peroxide – has been used for some seed.
Soaking in water or tea does help since seed must absorb water to start the germination process. Since peppers do not have a hard seed coat, it is less likely that hot water or scarification will speed up the process. There is some scientific evidence that GA3 will speed up germination.
Experimental Setup for Pepper Seed Germination Test
Seeds were collected from a red grocery store pepper. In previous years these seeds germinated well. Batches of 15 seeds were treated in different ways and then all seeds were germinated using my improved baggy method (see video below). This method allows you to easily see the seed and determine when germination occurs. The seeds were then incubated between 29C and 31C (84-88F). The ideal temperature is in a range of 27-32C (80-90F).
Baggies were checked daily to count the number of germinated seeds. A seed is considered to be germinated when even a tiny bit of the radicle (root) shows outside of the seed coat.
The following treatments were used.
- Control – no pretreatment.
- Water soak – 24 hours in tap water.
- Tea soak – 24 hour soak in cold black tea.
- Hot water soak – hot water was poured over the seeds and allowed to soak for 24 hours.
- Freezer – dry seed was placed in the freezer for 48 hours.
- Stratification – seeds were scarified with nail clippers as described in this video.
- Peroxide 10- seeds were treated for 10 minutes with 3% peroxide and then placed into a baggy.
- Peroxide 1 – seeds were treated for 1 hour with 3% peroxide and then placed into a baggy.
- GA3 – using Dr. Dino’s simplified method as shown in this video: How to Use GA3 to Speed Up Seed Germination.
Experiment Results
The following table shows the number of seeds that germinated each day. Day 0 is the start of any procedure. For example, the seeds in the freezer were put in the freezer on day 0 and put into a baggy on day 2. Day 0 for the control is the day they were put into a baggy. Nothing germinated on days 1 or 2, (d3=day 3).
None of the pretreatments reduced the germination time. GA3 gave a more even germination, but that is not of much help to a gardener and the extra trouble of using GA3 is not really worth the effort.
The freezer treatment is a common recommendation but it actually delays germination. As a side note, freezing seed is not a good idea unless the seed is very dry. I would not use this method for any seed. Note: Seeds in the freezer continued to germinate until all germinated by day 10.
Soaking in water, tea or even hot water produces the same germination time as the control, except of course you waste one day doing the soak.
Scarification is also not worth doing, and it might even lead to some rotting seeds. I have noticed this with other types of seed. The fast access to water, or perhaps the cutting process itself, harms the seed. The seed coat of peppers is not hard enough to require scarification.
Best option – just use my improved baggy method – see video above.
Sexing Peppers
Results From Another Experiment
A similar experiment was conducted by Daisy Dawes who also used proper controls. She tested four kinds of chili peppers: Jalapeños, Cascabel, Camba and Cobincho.
The pre-soak methods in this experiment did not speed up the germination process.
Should You Prune Pepper Seedlings?
It won’t affect the heat of the fruit, but pruning does affect when plants fruit and how they grow. Find out more in Should You Prune Pepper Seedlings?
Growing Hotter Peppers
What causes some peppers to be hot and how do you make them hooter? Find out in Growing Hot Peppers – What Makes Them Hotter?
Best Way to Start Pepper Seeds
The above experiments were done with fairly fresh seed. Results may be different for very old seed – but I have my doubts. If someone wants to supply seeds that are both old and difficult to germinate, I will redo the test with them.
People do report slow germination for pepper seeds, but I think the main thing you can do to germinate them faster is to get the temperature higher. At 30C ( 87F) they germinate quickly. And even at a lower temperature they only take a couple of weeks – that is not a long time.
Why do people report that various pretreatments speed up germination? I believe it is because they do not include controls in their testing. They assume their method is faster when it’s not.
If you believe your pretreatment is better, then repeat the above experiment as I have done, using a control and the baggy method, on the same batch of seeds. Let us know what you find in the description below – but include details of your experiment.
Learn More About Germinating Seeds
This playlist is a complete course on germinating seeds that will answer most of your questions. The same process works for all kinds of seed.
Excellent as always. I was warned by a grower that extended soaks in hydrogen peroxide can reduce the germination rates of some varieties/species. I’ve generally observed (without collecting data unfortunately) that popular varieties of pepper such as many of the Jalapeno varieties and many of the bell peppers (California Wonder comes to mind) generally need no special treatment beyond providing favorable conditions for germination (assuming you invested in good quality seed).
I work for a small greenhouse and we were struggling to germinate some pepper varieties. So I did a small experiment that looked at using a KNO3 soak for Carolina Reaper, Bhut Jolokia Red, Trinidad Scorpion, and Giant Ristra peppers. The seed was soaked in a 1.5% Hydrogen Peroxide for 5 minutes to kill any pathogens on the seed surface then was soaked in a warm KNO3 solution mixed at a rate of 1 teaspoon of KNO3 per quart of water for 24 hours at 80 degrees F. The seeds were then removed from the solution and patted dry. Both the control and treated were placed in 1 quart zip closure plastic bags with a folded and moistened paper towel with separate bags for each variety and treatment. Seed was checked daily for germination (radicle emergence). At the end of one week the germination rates were as follows. Carolina Reaper; Control 60%, Treated 100%. Bhut Jolokia Red; Control 75%, Treatment 95%, Trinidad Scorpion; Control 50%, Treatment 80%. Giant Ristra; Control 40%, Treatment 90%. The germinated seeds were sown into a 128 cell plug tray and covered with .25″ of medium vermiculite to grow on before being transplanted to their final pot size. Following this experiment I started using the KNO3 treatment on any pepper variety that showed historically poor germination rates and have been relatively happy with the results. Speed of germination was of less of a concern than total germination rate.
The value of my data is limited by several points including the following; small sample size (50-100 seeds per variety), short duration of the experiment (one year only), lack of known easy to germinate control variety, and lack of daily data collection.
If I was to do the experiment again I would want to look at the effects of H2O2 concentration and soak times, the effects of KNO3 concentration temperature and soak time, substituting a sodium hypochlorite dip for H2O2 (and collecting data on the effects of concentration and time), increased sample size, and collect daily germination data.
You don’t need that many seeds to get good data.
Did you get daily numbers, or just a number after 1 week? The number seem significant, but maybe the nontreatment caught up to the treatment numbers by day 9?
Several studies of peppers use the peroxide soak followed by KNO3 soak to speed up germination. I would have tried KNO3 but didn’t have any. I assume it does speed up the process.
It would be good to redo the experiment with some old seed where you know the control takes at least 3-4 weeks to germinate, or ones that won’t germinate at all.
I have been using a hydrogen peroxide treatment with a KNO3 soak on all of my extremely hot pepper varieties (1.1 million+ Scoville) and have found significantly reduced time for germination (using a paper towel method). I have not run any experimentation myself but have found some peer reviewed articles from universities and horticultural organizations that provide all their experimental setup and methods. It seems to matter more when it comes to slow germination type seeds or those with notoriously hard shells.
https://journals.ashs.org/hortsci/view/journals/hortsci/43/7/article-p2259.xml?fireglass_rsn=true#:~:text=Potassium%20nitrate%20solution%20has%20long,1993%3B%20McDonald%2C%202000).&fireglass_params&tabid=a41224c78be01746&application_server_address=mhtstiptiep002.esaproxy.local&popup=true&is_right_side_popup=false&start_with_session_counter=1
This link shows a thorough experiment and all data. Cheers!
This is a great post, thank you. I got hold of my chilli seeds a bit later than is ideal for my climate so tried soaking them in tap water before using your baggy method and sticking them in my propagator. I was worried I may have gone wrong by not trying other methods to speed them up, so it’s good to see that I can probably actually skip the soaking in future! That said, some of my seeds were several years old (they have been in storage while I’ve had no garden) so I can see the plausibility of pre-soaking helping them to germinate more than my newer seed. I have some of the oldest seed packets left over, so maybe that’s an experiment for next year!
I read somewhere that smoke extract improves germination.
That works for some specific species of plants – I doubt it works for peppers.
Keep doin what your doin Bob! I appreciate it.
Sufficient moisture and heat seems to be the key. We always started them in flats on top of a heat mat and covered them with newspaper or other material to help insulate the soil until they popped up.
Seems to me the secret is to ignore all the fads, apply the correct temperature & don’t worry about germination taking an extra day or two.
On germinating old seeds: Found a box of unused seed packets from 1996 last year, both flower & vegetable & tried them on both paper towel & compost.
Out of 30 packets tested using 20 seeds from each, only lupins (Russell hybrids) & Little Gem cos lettuce germinated – 19 lupin(!) & 1 lettuce. The rest of the packet of lupin seeds all germinated & out of interest, I allowed the lettuce to mature & flower, collected the seeds & the first lot sown germinated last week – free lettuce seeds. 🙂