Winter watering

[fanaticactus]

Now that we're approaching the time when my cacti will have to stay in the greenhouse for the colder weather, I'll have some winter care questions--even after many years of collecting and caring for these babies.

My first question is about watering. I generally have not given any water to cacti from October through early March, except a couple of ounces to Parodia (to prevent root loss and function) and the Epis and Zygos. But I've noticed that in online care information, many sources say 'less water' during the winter. Does that mean they should be given some water, even though they're in a greenhouse with a small heater that I try to keep just either side of 40F (4C)? Other sources say they should have no water at all.

I'm currently updating my Gymno section of my 'care pages'. I also have a new Echinocereus bonkerae, whose care stipulates more than average water than other Echinocereus and 'less' water during the winter. To me that still means some water. This will be my first winter with it, and I don't want to lose it.

Can anyone help clear up these apparent contradictory statements?

[Steve Johnson]

Can anyone help clear up these apparent contradictory statements?

The statements are contradictory because too many sources want to "paint with a broad brush" when they don't distinguish between cacti that are rot-prone and cacti that aren't. Although I'm growing only 65 species, hopefully the following list will be representative enough give you some ideas regarding what to do in fall and winter:

• No water at all

Ariocarpus fissuratus
Aztekium ritteri
Cephalocereus senilis
Copiapoa hypogaea, laui, and tenuissima
Coryphantha retusa
Cumulopuntia fuaxiana
Epithelantha bokei, micromeris, and micromeris dickisoniae
Eriosyce duripulpa, napina glabrescens, and odieri
Espostoa lanata
Frailea castanea and grahliana
Geohintonia mexicana
Gymnocactus ysabelae
Gymnocalycium baldianum, ochoterenae vatteri, stellatum, and stenopleurum
Mammillaria guelzowiana, matudae, perezdelarosae, spinossissima, and theresae
Pelecyphora aselliformis and strobiliformis
Pilosocereus azureus
Puna clavarioides
Rebutia heliosa and pygmaea
Sulcorebutia callichroma longispina, heinzii, and rauschii
Turbinicarpus jauernigii, klinkerianus, polaskii, pseudomacrochele, pseudopectinatus, and valdezianus
Wigginsia vorwerkiana

• Light watering every 3 weeks

Discocactus buenekeri and Melocactus matanzanus (required so that their roots don't die off to the point of no return in winter)

• Light watering every 4 weeks

Astrophytum asterias, capricorne, 'capristigma', and myriostigma
Coryphantha hesteri
Cumarinia odorata
Echinocereus rigidissimus rubispinus and viridiflorus canus (required so that they don't lose their roots in winter)
Mammillaria crucigera, deherdtiana, and grahamii
Obregonia denegrii
Parodia subterranea (required so that the plant doesn't lose its roots in winter)
Stenocactus lloydii and zacatecasensis

• Deep watering every 4 weeks

Eriosyce senilis
Tephrocactus articulatus inermis and articulatus papyracanthus

Light watering means that you want to moisten the mix without accidentally drenching it -- sip, don't soak. This is something you'll have to develop a feel for, but it isn't difficult. If you're able to maintain an overnight low of 40-42F in your heated greenhouse consistently throughout fall and winter, I think you'll be fine. Just be careful about it in case you see dips down into the 30s.

[greenknight]

The generalized instructions they give also fail to take local conditions into account. Here in the coastal Northwest, we often have long stretches when the weather is wet and cool, little or no heat is needed for the cacti and humidity is high. I don't worry about the cacti getting too dry in those conditions. Other times, we can get a cold, dry air flow off the interior. It can get very cold, a lot of heat is needed, and heating that already dry air makes the humidity extremely low. This sucks the moisture out of the cacti and their soil, more watering is needed then.

I don't have a greenhouse, my cacti are wintered in a cool room indoors, but I'm sure the principle is the same - you have to adapt your treatment to the conditions.

Tephrocactus articulatus needs winter watering? Huh, I've never given my "inermis" any at all. It does seem awfully slow to come out of dormancy, though - maybe I'd get more spring growth if I didn't let it get quite so dry.

[From0to10in2weeks]

• No water at all

Ariocarpus fissuratus
Aztekium ritteri
Cephalocereus senilis
Copiapoa hypogaea, laui, and tenuissima
Coryphantha retusa
Cumulopuntia fuaxiana
Epithelantha bokei, micromeris, and micromeris dickisoniae
Eriosyce duripulpa, napina glabrescens, and odieri
Espostoa lanata
Frailea castanea and grahliana
Geohintonia mexicana
Gymnocactus ysabelae
Gymnocalycium baldianum, ochoterenae vatteri, stellatum, and stenopleurum
Mammillaria guelzowiana, matudae, perezdelarosae, spinossissima, and theresae
Pelecyphora aselliformis and strobiliformis
Pilosocereus azureus
Puna clavarioides
Rebutia heliosa and pygmaea
Sulcorebutia callichroma longispina, heinzii, and rauschii
Turbinicarpus jauernigii, klinkerianus, polaskii, pseudomacrochele, pseudopectinatus, and valdezianus
Wigginsia vorwerkiana

• Light watering every 3 weeks

Discocactus buenekeri and Melocactus matanzanus (required so that their roots don't die off to the point of no return in winter)

• Light watering every 4 weeks

Astrophytum asterias, capricorne, 'capristigma', and myriostigma
Coryphantha hesteri
Cumarinia odorata
Echinocereus rigidissimus rubispinus and viridiflorus canus (required so that they don't lose their roots in winter)
Mammillaria crucigera, deherdtiana, and grahamii
Obregonia denegrii
Parodia subterranea (required so that the plant doesn't lose its roots in winter)
Stenocactus lloydii and zacatecasensis

• Deep watering every 4 weeks

Eriosyce senilis
Tephrocactus articulatus inermis and articulatus papyracanthus

This is incredibly helpful. Thanks so much! Is there a resource like this for other species? Best.

[esp_imaging]

The generalized instructions they give also fail to take local conditions into account.

^This. If you have warm, sunny, dry winters, cacti will want/ cope with more water.
Cold, cloud and wet / humid conditions mean cacti will want / tolerate less.

Plus many plants are reasonably accommodating.

It won't make much difference for many plants if you give them no water from October to March, or (if they are kept well above freezing) the occasional light watering. There are exceptions too - I water Austrocactus occasionally all through the winter, even though they may occasionally still be slightly damp when it freezes.

[esp_imaging]

This is incredibly helpful. Thanks so much! Is there a resource like this for other species? Best.

Coming from the UK, with extremely fluctuating weather patterns, I'm afraid I would find Steve's rigid watering schedule inappropriate.
If it's cold and extremely damp, I wouldn't water; mild, sunny and dry, then maybe a little to some plants if I felt they may benefit from it.
I'd also argue a bit where different species fall in the range of watering needs - Rebutias can be tolerant of a bit of winter wet, for example.

If you are looking for an accurate list of how to treat each of your plants in your growing conditions in Berlin, in your potting mix, I think you will be disappointed.

[From0to10in2weeks]

If you are looking for an accurate list of how to treat each of your plants in your growing conditions in Berlin, in your potting mix, I think you will be disappointed.

That's a fair point of course. And a realisation that I came to accept in the last months as it relates to watering...
Still, there must be some guidelines. Perhaps the question needs to be rephrased: which species are more or less susceptible to root rot in dormancy?

Best.

[Cactipack]

Can anyone help clear up these apparent contradictory statements?

The statements are contradictory because too many sources want to "paint with a broad brush" when they don't distinguish between cacti that are rot-prone and cacti that aren't. Although I'm growing only 65 species, hopefully the following list will be representative enough give you some ideas regarding what to do in fall and winter:

• No water at all

Ariocarpus fissuratus
Aztekium ritteri
Cephalocereus senilis
Copiapoa hypogaea, laui, and tenuissima
Coryphantha retusa
Cumulopuntia fuaxiana
Epithelantha bokei, micromeris, and micromeris dickisoniae
Eriosyce duripulpa, napina glabrescens, and odieri
Espostoa lanata
Frailea castanea and grahliana
Geohintonia mexicana
Gymnocactus ysabelae
Gymnocalycium baldianum, ochoterenae vatteri, stellatum, and stenopleurum
Mammillaria guelzowiana, matudae, perezdelarosae, spinossissima, and theresae
Pelecyphora aselliformis and strobiliformis
Pilosocereus azureus
Puna clavarioides
Rebutia heliosa and pygmaea
Sulcorebutia callichroma longispina, heinzii, and rauschii
Turbinicarpus jauernigii, klinkerianus, polaskii, pseudomacrochele, pseudopectinatus, and valdezianus
Wigginsia vorwerkiana

• Light watering every 3 weeks

Discocactus buenekeri and Melocactus matanzanus (required so that their roots don't die off to the point of no return in winter)

• Light watering every 4 weeks

Astrophytum asterias, capricorne, 'capristigma', and myriostigma
Coryphantha hesteri
Cumarinia odorata
Echinocereus rigidissimus rubispinus and viridiflorus canus (required so that they don't lose their roots in winter)
Mammillaria crucigera, deherdtiana, and grahamii
Obregonia denegrii
Parodia subterranea (required so that the plant doesn't lose its roots in winter)
Stenocactus lloydii and zacatecasensis

• Deep watering every 4 weeks

Eriosyce senilis
Tephrocactus articulatus inermis and articulatus papyracanthus

Light watering means that you want to moisten the mix without accidentally drenching it -- sip, don't soak. This is something you'll have to develop a feel for, but it isn't difficult. If you're able to maintain an overnight low of 40-42F in your heated greenhouse consistently throughout fall and winter, I think you'll be fine. Just be careful about it in case you see dips down into the 30s.

Steve, what type of mix do you keep your Melocactus/Discocactus in?

[Steve Johnson]

All the points here are well-taken, and what I posted does have a caveat -- the grower's local conditions rule, and if your conditions are substantially different from mine, you'll need to determine what's best through your personal observation and experience over time. Unfortunately there are too many variables which can't be accounted for in the "one size fits all" guidelines we see on the web. Even the most experienced growers started out as beginners, so I'm sure that trial and error has to be part of the process for growers who are just getting into cactus cultivation.

Steve, what type of mix do you keep your Melocactus/Discocactus in?

I add about 20% soil to my pumice and granite gravel mix. Not sure if the soil even needs to be there, but this works for me.

[fanaticactus]

I really appreciate all the helpful information you have all sent. It is most expedient to give you all a big collective Thank You! instead of trying to respond individually. The universal message I'm getting from all over is that winter watering (the amount and how often) depends largely on what the specifics of the local growing zone are, even though the cacti might be wintering over in a slightly heated greenhouse not connected to the house. I don't have many of the specific species you all mention, but am I right in assuming that, for example, if one Rebutia requires a certain 'schedule' for watering that ALL Rebutias should be treated the same? I realize that in larger genera that hail from very diverse regions--Echinocereus, for example--all specimens probably cannot be treated the same.

I have read in multiple sources that Parodias have such fine root systems they should all be watered very lightly about once a month to maintain the efficient functioning of the roots, or else they dry up. I can't tell from the responses if most of you have found this necessary or true in your personal experiences. I will be copying these pages and highlighting the ones I have to at least get a feeling of what I will have to be doing this winter to keep all my 'babies' happy and healthy for the next growing season.

[7george]

I have read in multiple sources that Parodias have such fine root systems they should all be watered very lightly about once a month to maintain the efficient functioning of the roots, or else they dry up. I can't tell from the responses if most of you have found this necessary or true in your personal experiences. I will be copying these pages and highlighting the ones I have to at least get a feeling of what I will have to be doing this winter to keep all my 'babies' happy and healthy for the next growing season.

I don't agree about Parodias loosing roots, at least I haven't such cases keeping adult plants dry whole winter. Thinner roots often dry up even summer time so this is not a real loss. The other thing is that Notocactus and Eriocactus groups plants are quite water tolerant so you can water them even in winter several times if it is not so cold around. Small seedlings & tropical cacti are different thing: they have to be kept at milder conditions and watered regularly, maybe once a month or after visible shrinking.

Real Rebutia plants are also tolerant to winter Watering but be very careful and better keep dry Weingartia (Sulcorebutia) and Aylostera belonging species.

[NiklasTyreso]

Different cacti originated in different climates and have different needs, but...

I have found it easier to kill cactuses in the winter by watering them, than by not give them water.

[Steve Johnson]

Tephrocactus articulatus needs winter watering? Huh, I've never given my "inermis" any at all. It does seem awfully slow to come out of dormancy, though - maybe I'd get more spring growth if I didn't let it get quite so dry.

I can do it because I live in Zone 10b, and overnight lows below 40 are unusual in my part of LA. Even though you live in Zone 8b, keeping your cacti indoors for the winter should protect your Tephros well enough for occasional watering. However, there is one factor for you to consider...

I keep my entire collection outdoors 24/7/365, and the winters here in coastal SoCal tend to be much warmer than what you'll experience up in Washington. My Tephros got awfully pruney in the years when I didn't water them at all during fall and winter, but once I started giving them deep watering every 4 weeks, I was amazed to see how much water they could take up when they plump and stay that way throughout winter. I don't know if your wintering room is warm enough in the day to justify deep watering, so you may want to consider light watering instead.

Weird thing about these Tephros of mine -- the inermis keeps its segments intact, but my paper-spine likes to drop them. I could never figure out why or if there's a way to prevent it, although this may be due to the rather high humidity in my area. Kind of annoying, but I still love the plant.

[7george]

Weird thing about these Tephros of mine -- the inermis keeps its segments intact, but my paper-spine likes to drop them. I could never figure out why or if there's a way to prevent it, although this may be due to the rather high humidity in my area. Kind of annoying, but I still love the plant.

I read somewhere that keeping that Tephrocactus dry more or less prevents its segments from easy dropping but I do this anyway and have no fallen heads...

[greenknight]

I keep the room where the cacti winter above freezing, otherwise the temperature varies with the outside temperature - which varies a lot. When it's warmer it's generally very humid (pouring outside). When I do water in the winter it's just a few squirts with the sprayer bottle to moisten the surface.

My Tephro has never shriveled visibly. I've only had 2 plants ever lose their roots over winter - Echinopsis ancistrophora and Parodia haselbergii. The Echinopsis re-rooted easily, the Parodia has been a struggle. Both were overdue for larger pots when it happened, since then I take into account how root bound the plant is when deciding whether to water it during dormancy.

The only other problem I've had from winter dryness is my unidentified monstrose Opuntiad, which has some tip die-back if I don't give it a little water.

I've had more losses from fungal (apparently) attack. Usually the plan dies from the bottom, but my old Parodia erubescens developed mold in the crowded dead blossoms on top of it. By the time I noticed, rot had spread into the stem. I could have topped it and gotten offsets, but I already had a rooted offset and a volunteer seedling (I'd thrown out many more, just kept the best one), so I tossed it.