Brown Spines on Agave stricta

Q. A quick question about a newly planted Agave stricta. Within 2 weeks of planting the spines have begun turning brown from the tips down. Do these plants generally brown out in the cold or is this one dying? It is a 15 gal plant - purchased from a local cactus nursery. It had some brown on a few stems shen purchased, but not like this. It was planted according to the instructions from the nursery with a sand/soil mix at bottom and sand around the perimeter.

Click here to see what Agave stricta looks like

A. I had to look up that particular agave because I did not know it. There is some information about it at the San Marcos nursery website

http://www.smgrowers.com/products/plants/plantdisplay.asp?plant_id=84

It is found growing in southeastern Mexico in its native habitat at about 5000 feet from what I could find. San Marcos nursery says it will handle temperatures down to at least 20° F. This is for Agave stricta ‘Nana’ so I am wondering if this is what you have or not.

A. stricta is confused with A. striata a lot because they look almost identical. This particular cactus may benefit if it's not placed in a location where it receives very hot direct sunlight in the afternoon. It sounds like it is a little bit delicate perhaps because of where it grows and its elevation.

Click here to see what Agave striata looks like

I am thinking you may have one of two or three things going on with yours. I don't think it's temperature. If this cactus was growing in a shaded or semi shaded area and then placed into an area that receives a lot of direct sunlight in the late afternoon it's possible that it could be sun damage.

How you planted this cactus sounds fine but if you are watering it too often, even with good drainage, this could also cause problems. When water is scarce it relies on internal storage of water. During the summer I would not water it more than every three weeks if you are planning to push some growth.

If you're happy with that size, you can water it less often than that. It is also possible that the soil mix that was used could have been a little too saline. Flush the soil with several gallons of water a few times to remove any excess salts if you think this might be a problem.

But I do not think it is a temperature damage but more likely to be sun damage or damage from irrigation. During the winter you should be able to water only once or twice during the entire winter.

Further thinking, it is POSSIBLE it could be a salinity problem. There are soil mixes out there that use sands with lots of salts in them and they are not washed sands. Wash plenty of water through the soil where you planted a couple of times a few weeks apart to reduce salt problems. Now is a good time to do that because temperatures are cold and tolerance to lots of water in the soil is much higher in plants during cool or colder weather.