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The Best Temperature to Germinate Chillies

Chillies can be quite tricky to germinate. Some of the hotter varieties in the C.Chinense species can be particularly slow to germinate, particularly when grown outside of their native climates. In the past i’ve experienced slow germination times of up to 1 month or more. One of the key factors that affects germination speed and rates is temperature.

It is generally accepted that the optimum temperature to germinate chillies is between 23-30 degrees Celsius (73-86 degrees Fahrenheit). If you can maintain your seed’s compost within this range then you should experience good germination rates.

In my experience, given a good temperature (i aim for 25 degrees Celsius) C.Annuums (such as Jalapeno, Cayenne) will often germinate within 2-3 days while C.Chinense’s will often germinate in 7-10 days.

Best Temperature to Germinate Chillies

Of course there are many different ways to get your seeds up to this temperature. A regular heated propagator is one of the best, as is my reptile heat mat method. Of course if you don’t have either of these you can place your seed tray in an airing cupboard or some other place with a constant heat source such as on a satellite TV receiver, on top of the refrigerator or on a desktop pc.


Temperature Stability

Stability of temperature is another key factor when it comes to improving both germination rates and times for hot peppers. It is surprising how soil temperatures can vary, even a high end thermostatically controlled propagator. As the ambient temperature around the propagator cools (usually over night) soil temperatures can easily drop off 5-10 degrees or more. This is particularly an issue if you’re germinating your seeds in a greenhouse or conservatory where night time temperatures can fall dramatically.

Obviously the best solution is to place your propagator in a place with as stable a temperature as possible. Personally I opt for the living room (much to my wife’s displeasure)! One other way I try and minimize these temperature fluctuations is to insulate my propagator with some regular bubble wrap. Doing so reduces heat loss as the ambient temperature drops off at night time.

Insulated propagator

Don’t forget to check the soil at least once per day as a higher temperature will dry the soil out quicker. I usually keep the propagator vents closed while waiting for germination to help keep the moisture in.

Hope some of the advise here has given you some good tips to help you reduce what can be the most frustrating part of growing chillies – particularly if you are as impatient as me!



10 comments… add one
  • ed June 19, 2014, 12:47 pm

    I need help growing my bonnets I can get them sprout or stay alive dont
    Now wat am doing wrong I have try green house.

    • The Chilli King June 23, 2014, 11:03 am

      Where did you get your seed from? Never buy seed off ebay.

  • Paul Blackman February 6, 2014, 7:34 pm

    Hi will a cool white fluorescent tube give out enough if any heat for germination ? I have at the moment got jalapeños, red demons , cayenne purple , scotch bonnet , mourga reds and Carolina reapers in separate plastic tubs in airing cupboard but have just set up fluorescent cool white tubes ready for the potting stage as was wondering when right time to put under lights !! This is my first time but I’m very keen and ambitious

    • The Chilli King March 3, 2014, 10:15 am

      Hi Paul,
      Yes the heat given out by cool tubes might be enough to aid germination so long as your set up is in a warm place (i.e. in the house). If you’re germinating in a greenhouse or shed then I would definitely suggest a heat mat or heated propagator. Good luck!

  • LDMA January 18, 2013, 12:40 am

    My first one showed just today…I expected the trusty ring of fire to show firstly as they are always quickest,…but no…Orange Hab…nice..

    • The Chilli King January 18, 2013, 9:23 am

      Nice – Orange Hab are one of my favorite varieties.

  • David Harley January 17, 2013, 3:18 pm

    I’m actually going to try germinate my seeds in my snake cage this year… reptile mat at the bottom, and a light that tuens on and off every 12 hours… will be interesting…

    • LDMA January 18, 2013, 12:42 am

      I’m doing the same thing, bought a red blue led light panel, have a big storage box, which I’m going to line with tin foil, have ordered reptile heat mats from ebay, and should have it up and running by next week. in time for my 1st shows to move over from the propagator.

      • The Chilli King January 18, 2013, 9:23 am

        I’ll be interested to hear how you get on with the LED lights. Ive yet to try these…

    • The Chilli King January 19, 2013, 7:59 am

      David – This sounds like the ideal environment. Let us know how you get on!

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