greenhouse temperature

The last few weeks have been busy. Spring has finally sprung in Hampshire. The garden is waking up and our Family and other Animals are demanding attention. The chillies have been quietly doing their thing on the window sill. After a sunshine-tastic Easter Bank Holiday it is time for a progress report.

Potting on…

Roots were starting to appear at the bottom of the smaller pots. A sure sign it is time to pot on. Not too big too soon or the plants will spend all their time growing new roots to fill the massive pot and forget to grow up top.

The same mix of soil was used. Seemed to work well for the first round of pots so why change it? No need for staking any plants yet. This time last year the Jalapeños and Big Bombs were already needing a small stake to stop them flopping over. Topping has helped the plant stability.

86 plants potted on. Very satisfying.

As a result of topping…

The plants have responded well to their growing tip being pinched out. Some plants were showing signs of branching anyway but others, less natural spreaders, have really bunched up and sent out side shoots galore. Excellent work. Although none of the topped plants have flower buds they all have many, many more growth points, rather than one leading spike.

A comparison of topped and not topped plants show significant differences (significant to us, anyway) Topping has slowed flower development, created more leaves, bushier and shorter plants. The non-topped plants are destined to be sold at a Summer Fete. They are tall, flowering plants with big leaves. They should do well in their new homes.

Not topped 7 Pot Bubblegum
Topped 7 Pot Bubblegum

Not topped Aleppo, with flower buds
Topped Aleppo

The late-to-be-sown Rocoto plants have just been topped. They are rapid growers and have a good number of true leaves. Snip snip snip. Time to bush out.

Last year the solo Rocoto plant we grew was a real pain in the greenhouse. Sprawling and brittle, it decided it needed other plants to support it. This made moving them around almost impossible. It was definitely worth the hassle (as is clear from the last minute seed planting) but there is nothing wrong with attempting to keep them more compact this year.

Moving up to the greenhouse…

The plants been up in our heated, bubble wrapped greenhouse for nearly a week and the results are good. All round light, controlled temperature and gentle air flow has really allowed the plants to flourish. We’ve been trying to keep the temperature above 15 degrees at night, so far no problem, despite outdoor temperatures hovering around zero. Temperatures during the day are less than perfect. It can often be well over 35 degrees in there, with window and door open. We’ve attempted some strategic placing of the hotter types on the South side and the ones that are less tolerant of high temperatures on the North side or somewhat under the shelving. Generally all the plants have added a couple of extra sets of leaves and are looking tip top.

There are a selection of plants that will be gifted to friends and family. These are not necessarily going to be potted on or placed in prime location though, just kept ticking along. They will be left in their first pots or potted on into odds and sods pots. A good chance to clear out any unwanted pots. These are in the cold frame, covered over at night and will be fleeced if a cheeky frost makes a surprise appearance.

Potted on ready to sell at the school Summer Fete.

All the Trinidad Perfume plants are showing good growth but have odd looking central new leaves. Pale and crinkly. Investigations and results will follow.

Trinidad Perfume plants showing signs of nutrient deficiency. Time to investigate.

Time to consider the feeding regime again. Should we increase the Chilli Focus mix to 10mls per litre? Should we go to twice a week or stick with once a week? Is an Epsom Salt spray needed again? And what about banana tea?

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…

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.
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.
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.
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.