How and when to water

[Steve Johnson]

After my previous note on the rain shelter I posted, this caused me to revisit my approach to watering in general. I know -- we're just a few weeks away from Christmas, and I already have the next growing season in mind. However, I figured that some advice on spring and summer wouldn't hurt as I think about the coming year.

For those of you who haven't already heard this before: I live in Los Angeles about 6 miles southwest of the downtown area. For the most part our climate is temperate, with temps in the 70s during spring, then heading into the 80s for the summer. Overnight lows average about 58-65. Being close to the coast, I typically enjoy late night and early morning low clouds (aka the proverbial "June gloom"), and I've seen it hang around all day from time to time, although rarely in July. Really hot spells (upper 80s to low 90s) can sometimes happen in August all the way through to the end of September -- downtown hit 100 a couple times in early September. Otherwise, I'm thankful that I don't live in the San Fernando valley!

All of my cacti and succulents are in terra cotta pots. I use a good cactus mix from the California Cactus Center (Pasadena, CA) with an additional 20-25% pumice added in for certain cacti such as Astrophytums and Turbinicarpus ss. When I started my new collection in June, my procedure was to water every plant once a week, using enough water to drain all the way through the bottom. While this was fine for hot weather, I'm now rethinking the possibility that maybe I wasn't paying attention to overwatering in the spring.

Here's my idea, and I'd appreciate any thoughts on whether or not I have it right. Basically, when daytime temps are in the 70s watering once per week should be moderate enough that cacti aren't getting more than a few drops coming out of the drainage hole. When temps are in the 80s, I'd like to see enough water drenching down through the bottom of the pot, again once per week. If there's a real heat wave, I could go with every 4-5 days for watering. However, I keep all of my cacti under shade cloth, so because my part of L.A. gets only infrequent hot spells into the 90s, I suppose weekly waterings wouldn't hurt them any.

This is my general concept, although I'm sure it's a bit oversimplified. In the interest of full disclosure, here is my collection:

Astrophytum asterias, capricorne v. senilis, and myriostigma v. quadricostatum
Cephalocereus senilis
Copiapoa hypogaea
Echinocereus pectinatus v. rubrispinus
Espostoa lanata
Gymnocalycium ochoterenae ssp. vatteri
Mammilaria microcarpus and spinossissima
Melocactus matanzus (comes in for some warmth when overnight temps go below 45 degrees during late fall and winter)
Neoporteria (Eriosyce) nidus v. senilis
Opuntia articulata
Sulcorebutia rauschii
Turbinicarpus macrochele v. polaskii, schmiedickeanus (could be v. macrochele or ssp. schmiedickeanus), and pseudomacrochele ssp. lausseri

The last time I grew cacti, I was going through a divorce in 1991. When I changed living situations, I was in an apartment that had no porch or patio access, so keeping any sort of collection was simply impossible. Now the situation has changed very much for the better, and after 20 years it was so nice to build a collection again. This gives me the chance to do a much better job with my cacti, so any thoughts, recommendations, etc. would be greatly appreciated. (With the online resources that are available, maybe I won't be as in the dark about all this as I was in my younger days.)

Thanks!

Steve

[toddo]

Hey Steve,

I live in northeast Long Beach and probably not to far from you so we pretty much have the same growing conditions. Sounds to me like you are doing a lot of things right. I'll point out some things where we differ a bit but neither are right or wrong, really. I grow in 90% plastic pots. I did the terra cotta thing for a while but in our climate things just dried out too quick. Plus, terra cotta takes up WAY too much space. Square plastic pots are where it's at in my opinion - saves ALOT of space and gets the most out of watering and reduces the frequency in which you have to. I water probably 3+ times a month (if that) for cacti from spring until November. Then none until a decent heat spell in spring. I probably grow a little harder than most but I like the compact growth I get and I'm never short on blooms. When the temps are above say 95+ or so I dont water at all. I've lost some nice ones watering when it's baking. Im sure the soil from CCC is decent - but if you bought it there you probably paid WAY too much for it.. Expensive place. I would also think that it contains a fair amount of organic material which ideally you would have none of growing the plants that you listed. I would ditch their mix and make your own. I use pumice around %60-%75+ mixed with decompose granite and or backyard crappy clay soil. Use the dirt in your yard and cut it with alot of pumice - it's great for cactus.

Hope that helps?

[Steve Johnson]

Thanks much, Toddo -- you have definitely given me some food for thought. Since you're in the Long Beach area, it's good to hear from someone who is pretty close to the climate conditions I deal with. I'll welcome hearing from other people with their own perspectives, and this is helpful to consider as I hope will be my best chance for successfully maintaining my collection. I just wanted to give you a couple of things to ponder:

1. Pots. I have always been a big fan of terra cotta. Just something about the look and feel of it, and I believed that it was better to let the soil breathe through the pot. However, I've heard from people with good success growing cacti in plastic pots. I can certainly see a major advantage to square pots just in maximizing space. Given the limited amount of space I have in such a small collection, I am tempted to bring in more plants than I would get with terra cotta. I welcome any other thoughts about terra cotta vs. plastic pots, especially regarding any particular factors that should be taken into account.

2. Soil. The right soil is very important, although I think there are a number of opinions on what "right" means. I don't have much expertise beyond knowing that the so-called "cactus and succulent" mix we get from Home Depot, etc. is useless. The California Cactus Center has been specializing in cacti and succulents for 30+ years, so the cactus mix they make has to be quite different from the commercial mixes I wouldn't take out of the average nursery on a bet. With that said, I suspect that I do see some organic material, although I wish I knew more about what's in their mix and whether or not it's good for cacti. I'd love to hear from someone who has actually been to the CCC so they can give me more direct experience on this. If that's not going to happen, the next best thing I can do is take a photo of a soil sample in case it would be enough to get an idea. Maybe the pic is enough to see any telltale signs of organic material. We can try, anyway.

I appreciate your advice, and I'll look forward to hearing any further ideas from others as well.

Steve

[iann]

For 90% of (desert) cacti, you just shouldn't bother watering them in winter. Little to gain, lots to lose. Following your saga with the rains, I couldn't imagine you wanting to add any more water to any of them until spring. A 2-3 month dry spell in fairly cool conditions is nothing to these plants. Most of mine stay dry for 4-6 months.

A few of the cacti you list would tolerate winter water quite well, but some definitely wouldn't. There are only two that I would deliberately try to get wet in winter. The Melocactus, but only if it is very warm since it is very much a tropical! The Eriosyce is from an actual Mediterranean climate, not that common for a cactus. It will get by with dry winter and summer water, but it will flower best at the end of winter if you water it during winter. Certainly once you see buds then it is ready for water. Its reputation for rotting, something I have never seen, may come from an intolerance of water in very hot conditions.

[Steve Johnson]

For 90% of (desert) cacti, you just shouldn't bother watering them in winter. Little to gain, lots to lose. Following your saga with the rains, I couldn't imagine you wanting to add any more water to any of them until spring. A 2-3 month dry spell in fairly cool conditions is nothing to these plants. Most of mine stay dry for 4-6 months.

A few of the cacti you list would tolerate winter water quite well, but some definitely wouldn't. There are only two that I would deliberately try to get wet in winter. The Melocactus, but only if it is very warm since it is very much a tropical! The Eriosyce is from an actual Mediterranean climate, not that common for a cactus. It will get by with dry winter and summer water, but it will flower best at the end of winter if you water it during winter. Certainly once you see buds then it is ready for water. Its reputation for rotting, something I have never seen, may come from an intolerance of water in very hot conditions.

When I continued my normal summer watering through the end of October, I realize that I made a big mistake. In fact, it cost me a very nice Turb (macrochele v. polaskii). I'm approaching my watering regimen with a lot more caution now, and I believe that any watering at all in October will have to be light. From November to the beginning of April, my cacti are staying dry under the rain shelter where I can monitor any "special needs" plants for the occasional winter watering that may be required.

I'm especially cautious about the Melocactus matanzus. During winter in L.A. we can get periods of warm weather going into the 70s, and 80s are not unheard of. The problem is that our winter weather can be so bloody variable, and I can't possibly anticipate if warmer temps go back down to the 60s (or even 50s) through a few weeks or a few days. Then there's the night situation -- would keeping the matanzus in at night with a space heater going 68-70 degrees be good enough for a touch of winter watering? I'm honestly not sure what to do, and I'm thinking that it would simply be better to keep my matanzus dry until spring. With that said, I wouldn't mind something more specific about the appropriate temps for the amount of time given with a spot of monthly watering for winter. (Sorry about that -- I must seem awfully fussy!)

Thanks!