Hardy Tropicals UK

Most people who grow Alocasia have those annoying episodes where a plant stops growing new leaves, and the old leaves start to deteriorate. What has happened is the Alocasia is not too happy with it's lot, and goes into dormancy, which is it's defence against unfavourable conditions. This mostly affects those requiring more tropical conditions in our long cool, dark winter.

Many people at this point bin the plant, but that is not necessary if you know how.

Ok, before we start, this procedure will not work with all Alocasia, The 'Jewel' type for instance like to be dry, so 'boiling' will likely lead to rotting, also Alocasia c Sarian seems to not respond, but most including the macrorrhiza, and odora family respond very well to this. Also 'Mayan Mask' is a good candidate.

Compost verses Air Bagging and Watering
Some people start them off in damp bags in an airing cupboard, but evidence is that is a bit hit or miss, and some fugal attacks seem to happen in damp air, that don't happen with damp compost. My preferred mix of compost is 40% coarse (sharp) sand, 20% pea gravel, 10% perlite, 20% loam, 10% multi purpose. This gives an extremely well drained, quick drying compost that Alocasia prefer in the UK, In warm to hot conditions (Min 20C) they can be left in a saucer of water, but in normal UK summer conditions they are better watered well, with warm to hot water, regularly, and left to drain. If you notice the plant stops and is going into dormancy, don't water, let it dry out, and wait for better conditions.

Ok, for this example I'll use my Alocasia macrorrhiza 'Black Stem'. This has tropical requirements, and by end of December, has had enough, even indoors. I then withdraw watering and tuck away indoors, until better conditions arrive. This time for me is from mid February, once the sun has some strength.

This year the Alocasia is in a 3 litre pot, inside a black ceramic pot holder. The pot holder being black is no accident, as the main thing with Alocasia is they thrive in warm, to hot, soil.
- First thing to do is soak the pot in 45 to 50C water to completely hydrate it.
- Then place the pot inside a plastic bag and seal the top.
- Place the bagged pot inside the pot holder (this gives thermal stability)
- Place the pot holder on top of a Radiator.

Within in a week my 'Black Stem' has exploded into growth. Until this morning I only new the temp was very warm, but have put a thermometer under the pot in the pot holder, and it is recording 43.1C (105F). It will stay on the radiator until proper leaves have grown which may be another 2 weeks yet, by which time the lounge windowsill will hopefully be warm and bright enough to stop it slipping back into dormancy.

Does this work with Colocasia too?

ourarka wrote:Does this work with Colocasia too?

Most Colocasia are far easier to start off. They only need 25C or so. Alocasia need higher heat than most people expect

LariAnn Garner has replied to my post on this on facebook.

LariAnn Garner For the record, I now have odora hybrid seedlings with black petioles. So the days of trying to grow the "black stem" mac are numbered. Knowing how dominant odora genes are, this hybrid will handle winters as well as my other odora hybrids (hope!).
12 hours ago · Unlike · 4

Wow, we could have a Black Stemmed Alocasia the size of x calidora then...... definitely on my wish list.

Going to try this method on mine this week. Thanks, Dave

Maybe they are growing too fast, the windowsill is going to still be too cold for a while, and not light enough on the storage radiator

Wow! what's the time difference between the two pics, Dave?

I just left mine growing this winter but I will try this if I get any more alocasia bulbs nice work Dave.

GREVILLE wrote:Wow! what's the time difference between the two pics, Dave?

If you hover the mouse pointer over the pic it show the file name, and my download adds the date and time the pic was taken. The first one was 21st Feb, and the second 24th Feb, so 3 1/2 days.

Mike, I'd keep them growing by choice, but with Black Stem I don't have good enough conditions. The lounge is down to around 15C in cold, sunless weather (most of this winter )

Mmmm this is one plant I can not get right !....I can get them growing then they seem to go dormant on me again\fail even in the summer. I wonder if I need to grom the in full sun here as we dont get much to start with......and maybe reduce watering.....its one plant that does my head in.

The Codfather wrote:Mmmm this is one plant I can not get right !....I can get them growing then they seem to go dormant on me again\fail even in the summer. I wonder if I need to grom the in full sun here as we dont get much to start with......and maybe reduce watering.....its one plant that does my head in.

I think you need to concentrate on the compost. Any compost that retains too much moisture is a disaster in cool spells, and you get a few of those even in summer.

Yes, put in the most sunny sheltered place you can.

Even consider a temporary mini greenhouse for the cold spells in summer and cover it...... where there is a will, there is a way

Now I have a problem.... the leaves are opening which means they need light, and still far to cold by the windowsill unless we get some sun, and none forecast for the next 5 days at least. I've now rigged up a table lamp next to the radiator. It only has a 5w CFL warm white bulb, but hopefully with Alocasia's ability to grow in quite shady conditions it will be enough.

Hmm. I may give that a go Dave. I have 3 gaganea that have gone dormant. Two are tiny though. Two odoras that are dormant. And one of my 2ft x calidora pups that has stopped growing and has only the one leave that now looks shabby. Been watering the x calidora pup from the base though and then sitting on top of my kitChen radiator but nothing happening. Have a gaganea and two odoras in the heated prop but nothing is happening either.

I notice its still sat in the bag.....so its keeping the compost mis fairly damp.....as the heat from the rad would normally dry this out at those temp's.

(Thanks for the technical advice, Dave ) Will keeping the Alocasia too cold at this stage bring back dormancy?