How to Grow Jalapeno Peppers from Seed

This fantastic, spicy South American food crop has never been more popular and by growing your own from seed you can really create those truly authentic dishes inspired by traditional Mexican dishes and regional cuisines now found throughout the United States.

These thick-walled 3 inch long peppers are often harvested green and used in many Mexican dishes. They are best grown in a greenhouse but if you start them off indoors early enough they can also be grown outdoors in the ground without protection.

Sow indoors around January for if you want them to establish quickly for outdoor planting or sow anytime up to the end of March for greenhouse growing.

Sow your Jalapeno pepper seeds - adequately spaced - into either plugs or a seed tray containing John Innes ‘seed’ compost. Top them off with another 1/2 inch of compost then gently water them in. It's important that the seeds remain moist until they germinate and as such will require adequate ventilation to prevent fungal rots. If ventilation is poor you may need to spray your newly germinating seedlings with a liquid fungicide once a week to protect them.
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Once germinated – this will be normally between 7 and 24 days - pepper seedlings will require plenty of light, in fact for optimal growth they will need between 12 to 16 hours of light a day. If the weather isn’t yet suitable for planting outside then they will need to be placed onto a south-facing windowsill but remember to turn them daily to keep them from acquiring a permanent lean.

Once the seedlings have produced four leaves they will be ready to prick out into individual pots, but you need to be careful so as not to damage the fragile root system. The safest way is to gently hold onto one of the sturdier leaves while using either a pencil or slim dibber to lift the roots as intact and undisturbed as possible. When re-potting, use either a standard multipurpose compost or John Innes ‘No.1’ or ‘No.2’ potting compost.

Grow them on for another couple of weeks and they will be ready for either the greenhouse or for planting directly outside into open ground once the threat of frosts is over. Make sure you choose a location that is in full sunlight and - if you have it - mix in some mushroom compost or other organic compost to help keep the soil fertile and moist.