Thursday, 14 July 2011

(Dis)obedient Orchids

On Valentines Day 2010 I was bought a beautiful flowering orchid. I was so excited I went out to buy a spray bottle and orchid food as soon as possible; as the label said, spray with water (and orchid food if desired) daily. Knowing orchids can be errr… tempormental, this has been a religious practice of mine and my boyfriend since we’ve had it. But it STILL hasn’t flowered! So I’ve done some research…

An orchid’s light source turns out to be more important than I’d imagined. I thought by keeping it out of direct sunlight I would do it a favour, as it’s normal habitat is the rainforest floor. However, it appears orchids do require direct light and it is the ANGLE that is important, i.e. it should come from above, the idea being it recreates the light path to the orchid through the canopy. The indication my orchid is too far from a window is that the single new leaf that has spouted in the last year is smaller and narrower that the others. This smaller leaf is therefore unable to store enough energy for the plant to bloom.

It also seems by not putting it near the window, I have restricted temperature fluctuations. These fluctuations are required to be around 25°c in the day time and around 17°c at night. These temperatures are important in the induction of flowering.

The last thing that appears noticeable is it’s pot and the water. It’s been in the same pot since I bought it, meaning an ‘old’ root system in clogged soil has built up, particularly when you relate the bog-standard softened tap water to the equation, which is apparently quite damaging. But watering my orchid with evian is pushing it for me. Collecting rainwater would be the most ideal non-damaging source, however living in a flat has it’s restrictions.

So this weekend, my orchid will be getting a new pot, with new potting bark. And a new position in the flat. Hopefully it will cheer up and I will have a beautiful flowering orchid once again. Stay tuned for pictures… Hopefully it'll be something like this

Thursday, 7 July 2011

Bags o' Bananas

Bananas. Perfectly lined up along a windowsill on a beautiful sunny day. My flat mate was trying to induce a faster rate of ripening among them (my other flatmate makes super good chocolate-chip banana cake which requires ripe, going on rotting, bananas). 

The Banana Ripening Process

Whilst this experiment is very clever; relying on sunlight and temperature to speed ripening, it quickly became apparent to me that’s probably not the way to do it.

I’ve always stored my bananas separately from my other fruit because it’s been proven bananas have a very high level of ethylene. Ethylene is a plant hormone known to induce senescence (fruit ripening, leaf death etc). So by keeping my bananas separate from my other fruit, I was preventing these from being ripened too quickly.

So then I thought, can the high levels of ethylene bananas produce be turned against them? I suggested the idea of enclosing the bananas and effectively trapping them amongst their own ethylene. And hey presto, the next day, super ripe bananas!

Bananas are often manipulated into ripening slower or faster by shops, and also at home. Now purchasable are ‘Banana bags’ a way to slow down the ripening process by storing them in the fridge. Claiming to keep bananas fresh for 2 weeks the bag works by insulating the fruit to prevent flesh over-ripening while keeping skin warm enough to prevent blackening. 

The Banana Bag

While at the other end of the spectrum, supermarkets use ripening rooms; bananas are picked green and are kept at 15-17oc (a low temperature will chill fruit and prevent ripening and a high temperature will increase ripening too much) and subjected to 0.01-0.04% ethylene in an enclosed room for 24 hours. The bananas are then subjected to carbon dioxide in the same conditions (minus ethylene) for 4 days. Banana temperature during this process can increase to as high as 32oC.

In summary, the bag works because it subjects bananas to higher ethylene concentrations than if they were exposed to air, and it also maintains a higher temperature which speeds ripening to the point of almost rotting. The chocolate chip banana cake was scrumptious too

More info at