Woody Minnich, shown here with my friends Hellen Adrian and Sheila Stevenson when we attended the 2012 Albuquerque cactus show and sale, gave a presentation at this year’s CSSA Cactus and Succulent Convention titled Secrets of Growing Quality Cacti and Succulents.
Photos provided by Alice Liles
Alice’s note: This story first appeared in my blog Cactus are Cool on July 5, 2013. I have told you about cactus being CAM plants in previous stories, but it is not an easy concept to understand, plus some of you might have missed the lesson, so here we go again. This time the lesson is a bit shorter and perhaps easier to understand, but sometimes we have to hear things more than once for the information to sink in. Plus, I had company on this trip that focused on CAM, so here we go.
Know what it is? To grow better
cactus? Water them at night. Really. Ready for a biology lesson? Well, botany
lesson, to be more precise. Here goes. Pay attention.
Woody Minnich, shown here with my friends Hellen Adrian and Sheila Stevenson when we attended the 2012 Albuquerque cactus show and sale, gave a presentation at this year’s CSSA Cactus and Succulent Convention titled Secrets of Growing Quality Cacti and Succulents. He also talked about it at this Albuquerque show. He assured us it really wasn’t a secret, but just a principle of biology that most people don’t know, and that I certainly did not know, which is that cacti and succulent plants are CAM plants, CAM being an acronym for Crassulacean Acid Metabolism.
And what does that mean? According to biology online, it is-and here is where you need to listen up-a CAM plant is one that utilizes the Crassulacean acid metabolism as an adaptation that conditions CO2 entering the stomata during the night is converted into organic acids, which release CO2 for the Calvin cycle during the day, when the stomata are closed.
Got that? Here’s more. CAM plants utilize an elaborate carbon fixation pathway in a way that the stomata are open at night to permit entry of CO2 to be fixed and stored as a four-carbon acid. Then during the day the CO2 is released for use in the Calvin cycle, which is a cyclical series of biochemical reactions that occur in the stroma of chloroplasts during photosynthesis, causing sugars and starch to be produced. In this way the rubisco is provided with high concentration of CO2 while the stomata are closed during the hottest and driest part of the day to prevent the excessive loss of water. CAM plants are therefore highly adapted to arid conditions.
CAM plants often show xerophytic features, such as thick reduced leaves with a low surface area-to-volume ratio, thick cuticle and stomata sunken into pits.
Like cacti and succulents.
Now-the short version from dictionary.com: any plant that undergoes a form of photosynthesis known as CAM, in which carbon dioxide is taken up only at night.
And photosynthesis is what makes your plants grow and bloom.
So, all of this is to say, water your cactus and succulents at night for optimum growth potential. Just because watering in the evening has always been a better fit for our schedule, it turns out my cactus have benefitted, and I didn’t even know why.
Just watering at night may seem too simple and easy to be true, but trust me, Woody knows what he is talking about. So give it a try with your plants.
And if you can’t do it at night or in the evening, an alternative is early in the morning, if that works with your schedule better.
And if you want to learn more of the technical stuff so you can amaze your friends and impress your enemies, read more at these websites:
