Shading Plastic Cups Seems To Improve Growth

It's been a poor year for fuchsias as far as I'm concerned. They just haven't grown. At least not for long periods. Then they have. Fits and starts the whole time. And the growth spurts seem to have coincided with warmer weather. This is strange, since fuchsias grow well in cool conditions (about 10 deg C (50 deg F)).

I had this great idea to grow cuttings in 200ml plastic cups because, being deep with low surface area, they seemed to offer great potential. But their greatest feature was that I could actually see the roots growing and how the plants were using water in the compost. It all seemed so ideal, just as lots of my ideas do at the time.

Alas, things did not turn out as planned. Whilst growing well in early spring, they suddenly stopped and hardly moved at all. After deducing this was because the compost was getting too warm in the strengthening sun, I popped the cup into a 3.5 inch plant pot to keep it cool. And guess what? They started growing.

Furthermore, I have also noticed that cuttings rooted in the centre of a perlite cup do so more quickly than those around the edge. This time I convinced myself it was somehow cooler in centre - another act of near lunacy when seen in the clear light of day.

Anyway, I read an article in the 'Science Daily Blog' last week (first published in December, 2008) which outlined that plant roots have a sensing mechanism to detect UV-B light levels. They then send signals which cause the plant to adjust its normal growth appropriately. I'm not sure exactly how this works, or in what way growth is adjusted. But it could nevertheless offer an explanation for fuchsia cutting growth: Perhaps it was the increased light intensity, not the temperature, which caused growth to slow down in both the compost and in the perlite. Still not sure, though. It could just as well be 'something in the air'.