North American burstgrowers at home - zone 6, humid :~

[exotica]

I must be dumb! For a week now I turn in circles and cannot find the topic where you guys talk about winter watering of plants from the Mojave region. I think (forgive me if I'm wrong) peterb wrote something about a transition zone between summer and winter rainfall, etc. By the time I started reading the posts I had to go, I thought I'd find it later, but I couldn't.

Anyway, I didn't write this new topic just to ask where to find the other. I wanted to ask something important for me. When you guys write about winter watering of these plants, what conditions do you mean? What are the day and night temperatures while the plants are wet in cultivation? What is the weather - sunny/cloudy? Air - humid/dry? How fast the watered plants should get their soil dry? What is the frequency of the waterings and when do you start to water - December? January?

[iann]

Lots of plants, much variation. I just watered Pediocactus. Last night was -3C and today reached 10C in the greenhouse.

Echinocactus polycephalus won't be watered until days are around 30C, although nights can still be around freezing.

In between there are Sclerocactus and the like. Mostly I give these plants water starting in late February and some time into April. By then the frosts are gone and days are consistently hot in the greenhouse.

[exotica]

(I apologize for the typo in the subject - zone 5 is far up north - I'm 6)

I also start watering my Pediocactus early, but not as early as January. Still waiting for the lowest temperatures to come and settle for a while. I start late February to early March. My plants are outdoors with just a PE sheet over them. With day <0 °C and night <-10 °C continuously, watering will kill them, I believe.

My question was particularly about plants like Pediocactus sileri, Echinocactus polycephalus, Sclerocactus polyancistrus, johnsonii and similar in cultivation. For many of those the prevailing amount of water they get is January to March, followed by a dry period April to June, which I still don't know how to simulate in cultivation.

iann, thanks for sharing your polycephalus experience. I've seen pictures of your plants in the other topics and it is obvious that you have the knowhow.

[iann]

Not much point watering snow-melt species until there is some melting

The easy way to simulate January-March rainfall is to water your plants between January and March Maybe a few weeks later to adjust for local conditions. Of course your conditions will be different from mine. In my greenhouse, things heat up very rapidly from mid February onwards although nights can still be very cold.

I checked my max-min and it read 14.2C for today's maximum. I wasn't here but there was almost certainly some sun on the thermometer, so hardly a warm day. With lots of plants available as guinea-pigs, I'll be watering more species earlier this year to see how they like it. From April onwards the greenhouse is in the sun all day and it very quickly gets too hot. Certainly by May the Pediocactus shut down and I let the whole group go dry until July or even August. Once they are thoroughly shrunken they seem happy enough to take on a little water.

Pediocactus sileri seedlings out in the greenhouse have been watered and are fat and happy. Also surprisingly highly coloured in the low light. The roots work quite slowly and it takes a strong nerve to leave them damp long enough to get properly fat, but they will get there because there is so little water loss at this time of year.

[exotica]

Yeah. Mojaveans will not do here without a greenhouse…

As for the others (the "snowmelters") - they live happily here with just the mentioned above basic rain/snow protection and care.
Here is the last year's cycle of one of my happy expats - Sclerocactus mesae-verdae SB303 (7 cm pot):
All the inflation, flowering and growth took place between the beginning of March and late June (and some secondary growth late August and September, completely dry from October on). I was amazed to see the actual growth of this fellow before wintering - 3 areoles per rib (see the scar from one of the flowers to the left of the last picture)!
04.03.2011: 18.03.2011: 23.04.2011: 13.11.2011:

I wish I could care about Mojaveans in a similar way, but I definitely need to invest in a Mojave simulator.

(Edit: removed the size numbers in the [img] tag to have the linked images appear in the new forum version).

[daiv]

Andrey,
That is an impressive photo series. That plant is definitely happy with your conditions.

I like the idea of a Mojave simulator! I think your biggest challenge there would be creating the intense sun? I wonder what else? A good heater and dehumidifier?

[iann]

I don't think you need intense sun or extreme heat to grow Mojave plants. People have tried that and failed. Although obviously some sun and some heat is important, plus sun and heat at the right times of year probably makes things easier.

All they seem to need is respect for their needs. Unfortunately these needs are very different from what most growers choose to give their cacti, or are even able to give them. Water when nights are below freezing but days are warm enough for shorts, and completely dry when it is over 100F, tough for people to imagine even if they can produce those conditions.

Many people never let their plants anywhere near freezing, and so those tough species just never grow. Looks like you might have seen how quickly they do grow when you hit the sweet spot. I was in the greenhouse today and noticed the Pediocactus have swelled from the water a few days ago. This is an earlier than usual test for me, now that I have enough plants to lose some, and I'll be giving more water when the sun comes back again. I haven't watered any E. polycephalus yet, I'm such a coward! -4C (25F) and still only 10pm here, I might have to go and switch the heating on.

[exotica]

A "Mojave simulator" is more a metaphor, as you got it daiv. A greenhouse does not apply well for Mojaveans as a term (I think). While a greenhouse would more likely to be open at day and closed at night, the "simulator" would be just the opposite for most of the time in order to achieve a big temperature amplitude and keep the RH relatively low.

You know, I've been thinking of a heat generating dehumidifier (i.e. a zeolite rotor one) for quite a while (dehumidifiers are my main business) and I have one such sales sample. But, no. I am looking for a way to be able to care for these plants here without technology (or something which has relevant monthly bills).

I've got a few months ago my first Mojavean - a Pediocactus sileri SB1872 (it is a rooted offset off a grafted seedling too, like my other "snowmelters"). It is my Guinea pig for the coming months, but without a "simulator" I don't have much trust in it's future… We'll see…

[exotica]

iann, we must have been writing our posts at the same time - sorry for missing yours while writing mine.
It was a pleasure to read your latest! I'm not one of those people that you describe. For the past 3 years I've lost a few other plants, but not a single Pediocactus or other of the kind. I have them growing and flowering and their happiness makes me happy. It is only that I do not have any experience with Mojaveans. Fear has big eyes. Honestly speaking, right now I'm afraid and that is my problem. Lack of experience and enough information to start with these…

[CoronaCactus]

Living in the Mojave, i don't have issues growing those plants, but i have yet to figure out how to properly grow Pedio's and other species that live under snow. (however, i dont have problems with Opuntia from cold/very cold climates) I obviously don't have frost/freezing/snow and without resorting to buying a large freezer to pay a nice electric bill for, i haven't figured out a way to provide them with proper growing conditions. I even managed to kill a grafted Pedio!

I feel your pain, Andrey!

[A. Dean Stock]

Perhaps you are using the term "Mojavean" in a very general way, but I live a few miles from colonies of Pediocactus sileri and I don't consider the area Mojave desert. I think that Colorado Plateau would be more appropriate since the area is at around 5000ft and quite unlike the lower Mojave Desert areas. Usually not all that hot in summer and many winters without much snow at the type locality for P.sileri. Some winters will get as low as -5F and have snow cover for two months as in the last three winters but this winter probably no more that a couple of minor snow storms that melted in a day or two.
Dean

[peterb]

Yes, Dean, I was going to say that Fredonia and that area is not strictly Mojavean. An interesting climate up there.

You are obviously a skilled grower, Andrey, and I would also urge you to use your intuition and observation. I remain skeptical of my own advice, sometimes thinking perhaps these "winter water" plants can be forced into the Chihuahuan box of dry winter/wet summer and still do okay. The jury is still out. I do know that with Phoenix AZ conditions, the biseasonal rain plants do way better with some winter water, as Ian said, when the days are warm no matter what the nights are like.

peterb

[exotica]

I'd like to thank you all for sharing your thoughts, observations, experience, remarks and advices.

You're surely right, Mojave's NE conditions are different than SW. But, both Pediocactus sileri from the NE and Sclerocactus polyancistrus and Echinocactus polycephalus ssp. polycephalus from the SW are equally a challenge for cultivation on roots. Especially in a relatively humid climate like mine in Sofia, Bulgaria.

Back to my Mojave simulator dream, I'm getting a clearer picture of a cold-frame equipped with a big container of sea salt as an absorbent against excess humidity. What do you think?

Actually, is RH a significant factor in keeping Mojaveans in cultivation, or they could tolerate a higher RH if their watering and growth cycle is accurately followed?

Another question. In some sources, which describe Sclerocactus polyancistrus and Echinocactus polycephalus ssp. polycephalus environments, I find "… they grow on extremely saline soils…". Does it mean salty (NaCl) soils, or it means highly mineral soils? As about Pediocactus sileri, it is written that it grows in areas with high gypsum content in the soil, but some sources say they live in gypsum areas, but they don't actually grow on gypsum - how to interpret this?

[iann]

I'm not sure that excess humidity is a big problem. Just don't water them at the wrong time, do water them at the right time, and don't be afraid to freeze them. Maybe Sclerocactus don't like humidity, but certainly Pediocactus do fine with it.

Saline soils are common in the Mojave. Might be Sodium Chloride, but are frequently extremely alkaline salts like hydroxides. Sclerocactus are frequently found on alkaline soils but I don't think Echinocactus are. I don't think either of them are really adapted to grow in salt (NaCl).

Gypsum is weird and harsh for plants to grow in, and pure gypsum is almost totally devoid of nutrients. Certainly P. sileri is found growing on/in it, but it is gypsum mixed with clay, and it is also found on other soils.

[exotica]

Thanks, iann!