Advice for growing cacti in the wet tropics

[Fungal Forest]

Hi everyone

Im new at growing cacti and I live in the wet tropics of north queensland. I have had some success with sprouting seeds both button and Trich's using the plastic bag method. Also I acquired some cuttings of T. pachanoi. I keep all plants under cover and inside a mini green house to protect from the rain.

It would be great to hear any tips or advice from more experienced growers. It is quiet dry at the moment and I would like to know how often I should water during the dry and if at all during the wet season as it gets very humid. Also when and how much I should feed them.

Any other advice would be great.

Thank you

Edited September 18, 2014 by fnqmane

[gtarman]

Hey mate. A lot of the general advice on cacti care would mostly apply as usual (ferts, watering)...the main thing I'd say is to just try and keep them in a dry spot. I don't think those mini greenhouses are a good idea, just because they encourage much higher levels of humidity and heat, which if you're in FNQ you'd already have both of those conditions by the bucketload.

The botanic gardens at Mt. Coot-Tha in Brisbane have a good setup in that regard...dunno if you've ever been there. But basically it's just a shed-type structure, with the roof being made of that semi-clear corrugated plastic - enough to give the cacti decent (slightly defused and dampened) sunlight, but to keep them from being burnt and to keep unwanted rain and humidity away. It was not an enclosed structure - plenty of airflow. But yeah that would give you heaps more control over your cacti's water intake and hopefully stave off the worst of the humidity.

[gr33ntea]

In Melbourne it has been wet and very cold. I would suggest you keep your cacti dry, like in a greenhouse or something.

Otherwise you catch root rot, fungi

[Nailthesnail]

I had a cactus in one of those mini green houses for a while it started rotting from the tip because of the humidity.

Would get them out and try have them in an open environment that doesn't get rained on.

[space cadet swami]

I'm in Nth Qld & I would say forget about the lophs, they'll just rot in the tropics...it's too humid. If you want lophs...graft to trichs. Just keep in mind that if you graft & they get a lot of water they'll more then likely split from growing too quick. My trich's sat outside during the wet with no probs...just make sure the mix drains really well. I add a fair bit of perlite or coarse sand in my cactus mix (I prefer perlite). I would definately do as "gtarman" said & ditch the greenhouse...too humid. Because most of the rain up here is during summer it's not too bad, but if you had a wet winter I'd put them under cover for the duration

Anyway, good luck with it...

[Fungal Forest]

Cheers for the response guys. I have the green house open unless there is heavy rain. I am worried about humidity but at this time there is none. note the plants have been through cyclone conditions just after rooting and seem to be going okay.

Another question, should I repot cuttings soon?

thanks

[Gunter]

It rains a lot in the wet season in the Andes, often more than meter in some areas.

These cacti, San Pedro allies, thrive with plenty of water and good drainage.

Don't treat them like other cacti, they do great with plenty of water in the wet season.

You likely get up to four meters of water in the rainy season, if you employ raised beds or pots with plenty of drainage you should be fine.

Edited September 18, 2014 by Gunter

[katu]

Forget about the lophs? Kadas garden is in the tropics and he seems to do alright. Providing your potting mix is mineralistic and you provide shelter from the rain I see no reason why you cant grow them successfully in north qld.

[woof woof woof]

Control the rain.... so under a transparent piece of plexi-glass roof ..... you'll be fine. I have the same prob where I live.

If you don't control the amount of water, they will rot and die super fast. Bridgedsi's seem to the be the weakest of the trichs in the sense that the are most susceptible to overwatering and drought. Peruvianus seem to be the strongest. Not sure about Cuzco's

Patchanoi's seem to be close behind peruvianus as rot resistant trichs go in my opinion

[Illustro]

In the wet subtropics/warm temperate of my clime, I manage to grow all sorts (Mammillaria, Rebutia etc) completely exposed outdoors. I just made a mix of about 60-70% coarse sand & pumice, then made a cone of mix (like a volcano) in the pots around the roots (empty space filled in with limestone gravel) as to ensure as little moisture was retained around the roots as possible. Three years and no problems at all. For the more sensitive species, I made a glasshouse/'rain shelter', designed simply to keep rain out and allow heaps of air movement (huge amount of venting) -- the babies love it.