Growing cotton on the balcony

On January 2nd this year I fought my way through a snowstorm to get to a garden centre. It was my last day in Germany and I wanted to pick up some packets of seeds to bring home. There were two customers there that day - me and someone buying a potted plant as a late Christmas present. But at least she'd arrived in a car.

The staff looked at me strangely - they clearly couldn't understand why this mad foreign woman had picked that particular day to buy a year's worth of seeds. But I got the things I wanted, some of which I knew I'd be unlikely to find easily in Italy. And more.

Amongst the things I found was a packet of cotton seeds (top left in the photo).

I bought it just for fun. The packet said it was easy to grow as a houseplant, so why not? It would make a change from the usual marigolds. The packet instructions said that it could be started off in the house all year round, so I got going immediately.

Well, a few seeds did germinate - but before long they'd toppled over and died. I think I may have overwatered - it's a plant which expects drought conditions. So I sort of forgot about it. Until a couple of weeks ago when I was planting biennials and came across the remaining seeds. The outside temperatures were well above the minimum by now, so why not stick it in and see?

And yes - for those of you who were trying to guess the mystery seedling of a couple of posts ago, I'm now growing cotton on the balcony. And by pure chance, the other day I found out that Milan's climate is classified as the same as those of the cotton producing states of the US - humid subtropical. I'm only surprised that it's not grown here commercially.

It germinated almost instantly, is growing rapidly, and I'm keeping my fingers crossed that there's enough time for it to do something before the colder weather arrives. The flowers are supposed to arrive after 35-45 days. They only last a few days, but flowering will go on for a month. That should take us from the end of August - still hot and sunny - till the end of September - getting cooler . It takes another month for the cotton bolls to mature - but I suspect it will be too late. By mid-October they'll need to be inside, and the plants are 3-4ft tall - I'm not sure I have room for an entire plantation in the flat.

We'll see. I could certainly bring one in. But if it goes wrong I shall definitely try again next year, starting earlier. If you'd like to try too, keep in mind the following :

1. The seeds need a temperature of 16°C/60°F to germinate and then at least 21°C/70°F to grow successfully. Start them off in March/April, in the house or greenhouse as necessary, sowing 2/3 seeds per 9" pot. Thin out any weaklings as they come through. The soil should be moist at first, but afterwards keep them fairly dry.

2. As they start to grow, transfer each plant to a 30cm pot and start watering. Again they should be slightly moist but never waterlogged. Feed weekly with a high potash fertiliser - they need high nitrogen and potassium. A liquid tomato food will do fine. If they've been started inside, they'll need hardening off gradually before being left out, and like all tall plants will need to be staked.

3. The plants are prone to red spider mite, so mist them frequently as a preventative measure.

4. Stop watering about 16 weeks after planting and let the plants dry up and the bolls finish forming. Pick them when they split open, showing the fluffy cotton,and you'll have your seeds for next year - but be careful of the prickles. If the bolls are exposed to rain they may rot, so pick them immediately and let them dry and open indoors.

Acknowledgements

Many thanks to Old Shoe Woman for making the photos of the cotton flower and boll available under Creative Commons Licence on flickr.