Why are the chilli plants a bit pale?

A south facing windowsill in March is no longer enough for the chillies in our lives. The leaves are a little limey in colour (especially the chinense types) and some of the plants just a bit leggy (especially the jalapeño and poblano). Without rushing for LED lighting and pinching out the tops just yet what can be done?

The key questions are would they do better in a warmer place? How can they get the most natural light? Do they need feeding more?

A bit of background information to give you a better idea of what we’re dealing with.

First temperature…

The chilli seedlings are currently in the house. You would hope that the house is a good temperature for the chillies to thrive. Monitoring with a maximum and minimum thermometer reveals that during the day, in particular cloudy days, the temperature can drop to as low as 17 degrees. At night an overnight low of…the same. Our house is pretty consistent.

In comparison, the heated greenhouse temperature has been all over the place. Sometimes 13 degrees at night, sometimes down to 5 degrees. It was zero outside but still, rather chilly for chillies! Sometimes 35 during the day. We have the smaller chilli plants in the greenhouse already. Although they are growing, they are no where near as advanced as the house ones. This is really the only other location we could consider putting the house plants. Perhaps quite yet.

Ideal chilli growing temperature range is 27-31 degrees. Well that is a hell of a lot hotter than these little babies have been getting. Time to raise our game and temperature. Off to turn the central heating on and research heating cables.

Now light…

Our two south facing windowsills can take five trays of twelve plants each but we have fifteen trays. The trays are on rotation to allow a fair share of being closest to the window and are lined up on a big table as close to the light as possible. It is March and we receive 12 hours of sunlight on a good day. However, on a double drip rainy day it can be really dingy. Clearly not enough light for those at the back of the class.

And then feed…

The plants are currently given a weak solution of Chilli Focus (5ml per litre) The bottle says they can be given 10mls per litre as the plants mature…perhaps it is time? Or maybe a nitrogen feed would be more suitable at this point and then switch back to the potash feed when flowers start to form. Or maybe Epsom salts might do the trick? Yes, a quick Google reveals that no harm can come from an Epsom salt spraying and a lot of good could be done.

Epsom salts are magnesium sulphate. Good for boosting chlorophyll production, uptake of nutrients and the ability to produce flowers and fruit. Best administered in a foliar spray it seems you can do no wrong with a misting of Espom Salts Wonder Spray (1 tsp per litre of warm water to aid dissolving).

The plan…

  1. The weather is turning from deluge of rain & 50 mph winds to cold and clear with some night time frosts. Until those frosts have passed we will have to stick it out in the house. It’s just not warm enough in the greenhouse.
  2. Keeping the central heating on in the house during the coldest days. The plants already come in off the window sills when the curtains are drawn.
  3. Moving the taller anuum type chillies nearer the windows to avoid any further legginess. The others will still be in the light. Turn the plants to encourage strong stems.
  4. An Espom salt spray will hopefully give a chlorophyll boost. Maybe that will compensate for the lack of prime window spots. We’ll continue with the Chilli Focus for now but…stop the press…a new click hole of banana compost has opened up. We get through a lot of bananas so this could be a good way to use the skins. We’ll report back.

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