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.
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.
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!