How to encourage blooming with no winter dormancy?

[Salazar]

Hello, I was wondering what else can I do to encourage blooming in cacti other than winter dormancy? I'm from a tropical climate so plants grow all year round.
Thanks!

[DaveW]

I suppose you could try giving them a dry season, provided they do not dehydrate excessively. They will only etiolate from lack of light in their rest season, not lack of water, therefore it may slow their growth enough to promote flowering the next year. I have always found "a near death experience" when kept dry, or unrooted has encouraged some cacti to flower, no doubt to hopefully pass on their genes through setting seed. I grew some Trichocereus in my centre bed in rich soil and they grew like mad but did not flower. I chopped a couple of four foot stems off intending to root them and left them standing on the greenhouse path and they flowered immediately without roots, plus did so the next year whilst still unrooted and all the time continuing to dehydrate. Therefore giving your plant a dry season by witholding water for a time may help. The picture below shows the Trichocereus still flowering leaning against the greenhouse end still unrooted the second year. As an indication the stems were probably twice that thick when originally cut, having dehydrated quite considerably when the picture was taken.

bridgesii.jpg (255.04 KiB) Viewed 3762 times

A nurseryman told me he visited cactus collectors in one part of India and whilst they grew tropical cacti at a much faster rate than we can, they too could not get plants like Sulcorebutia to flower reliably, since they had too warm winters. We in the UK with cool winters have no problem flowering them. Sometimes after trying a few times you have to choose the plants you can grow and give up with the others.

Many cacti do go dormant in the hottest part of the year, usually the dry season to avoid water loss, but how a humid climate may affect that I do not know.

The problem is human nature always wants to grow the difficult plants that are less suitable for our climate. You obviously have problems with cacti that need a cool winter rest, but then we in the UK have problems with tropical cacti. I suppose it is virtually impossible to provide cold through refrigerating a greenhouse, unless you are a botanical garden with deep pockets, but easier to provide extra heat in our cooler UK climate. You have quite a range of the more tropical cacti to choose from which we struggle to grow. A quote from the link below:-

"Many South American cacti, on the other hand, come from areas that are a bit more tropical than their North American brethren. Here we are looking at annual average temperatures between 20 and 25 degrees centigrade with increased precipitation (i.e., rainfall). As such, many South American cacti like gymnocalyciums, discocactus, melocactus, uebelmannia and even some copiapoa seem to be easier to grow in our climatic conditions."

http://www.philstar.com/modern-living/1 ... ti-tropics

http://www.philstar.com/modern-living/3 ... succulents

http://www.kadasgarden.com/Cwetcacti.html

[greenknight]

Give them a rest period even of there is no cold weather. Some cacti won't bloom much if at all without chilling, you may never get them to flower. There are other species that grow in the tropics and don't require chilling, but they go dormant in the dry season - so give them a dry season.
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I composed the above before DaveW posted his excellent reply, I totally agree with him.

[Salazar]

At what time of year do you recommend I dry them out?
We do have a dry season beginning around late February or early March and lasting until around mid May to early August.

[greenknight]

From what I can find about the Philippines climate, you're in the coolest season now (not that it's ever really cool). Right now would probably be a good time. A couple months rest should be enough. The time of year may not matter very much, anyway.

I had to laugh talking about "cool" weather there - here we're in a major cold snap, it hasn't gotten above freezing in days and there's 6 inches of snow on the ground.

[Salazar]

Thanks for your response because it's almost impossible to find anything on cultivating cacti in tropical countries.
Hope I'll get at least one bloom this year.

[greenknight]

There isn't a lot, it's true, but I did manage to find this from a guy in the Philippines - http://www.philstar.com/modern-living/1 ... ti-tropics

He reduces watering to once every 2 or 3 weeks from October to February. I'd say his experience is worth more than my educated guess.

[Salazar]

Thanks!

[7george]

Other thing you can do is to shorten the daytime for some of them - Schlumbergera for example don't bloom if no period with daylight 10 or less hours was not been experienced for several weeks or so. But you you have to study by yourself what species need short days to form flowers.

[Salazar]

The plants that I have are the common ones, Echinopsis, Mammillaria,Lobivia, Gymnocalycium etc.
What are you're experiences in encouraging these to genera to bloom?

[7george]

The plants that I have are the common ones, Echinopsis, Mammillaria,Lobivia, Gymnocalycium etc.
What are you're experiences in encouraging these to genera to bloom?

From those above maybe just Lobivia plants need real cold. Others - just some months of dry (and cool) rest. But all of them need to be in good condition, get enough sun and nutrients to flower. Many cacti don't bloom every year, so having just one plant of a species and see its flowers could be tricky.
Having about 100+ plants usually guarantee the success.