young spines on T. peruvianus dying

[ballzac]

The long spines on my peruvianus on the new growth have been going black and dying. Otherwise the cactus seems quite healthy and I'm not too concerned about it, but thought it might look nicer if it had more of those evil looking spines that it has on the bottom.

I remember reading something about it and the answer was that it was nutritional, but now I can't find the thread. I'm thinking maybe I'm overfeeding, but I'm only giving it half-strength maxicrop once a fortnight or less, so that should be alright. It is in full sun with all my other trichs.

It is hard to see the blackness in the photo, but I have a photo of pups from the original cut that this one was cut from that show it a bit more:

Also, my bridgesii has a lack of spines on the recent growth, and I'm guessing that whatever I am doing to my peruvianus to cause the problem, I am also doing to my bridge.

Any info or link to a relevant thread would be great.

EDIT: Oh, and as you can see the new spines on the peruvianus look a lot healthier than those from a month or so ago, so maybe I just mismeasured the food on one occasion or something

Edited February 11, 2008 by ballzac

[Ace]

Never seen new spines turn black on perus - quite possibly something to do with over-feeding (once a fortnight is still a fair bit for a cactus IMO - perhaps drop it back to once every 3-4 weeks?), but going off those above pics alone they seem more than happy as they are (black spines almost invisible to me, aside from one or two in the second Peru pic).

Your bridgie looks to be the same as mine - a somewhat recent cutting (maybe a season old now) that has started to put out a couple inches worth of growth? The lack of spines on the newer growth is probably due to lack of a mature root-structure, so at this point the energy is going into forcing out growth and spines are a secondary thing. I think once the roots start to get a bit more mature and form a neat, nutrient-sucking ball, the spines will become as they were on the mother before cutting. At least thats what I'm hoping with mine (same look as yours - looks to even maybe be the same clone).

Nice cacti!

[ballzac]

Cheers mate. Yes, the bridge is a recent cutting. In fact, so is the peruvianus. I guess that is probably the reason on both of them. Will still be more careful with feeding in future. I'm still a little new to all this. Like I said, they are otherwise very healthy, so I wasn't particularly concerned, but it's good to have an explanation. Thanks for your response.

[AndyAmine.]

IME trichs, being the fast growers they are love their food as long as it isnt overly N rich which I have found increases fungal problems like black spot/rot.

I feed mine every week during the growing seasion with a mid strengh dose of Maxicrop and full strength Yates Cacti and succ fert every 3 weeks. If I find they are asking for some more N then Ill supp with some morning pee or fish juice.

Then once every 3 to 4 weeks during the off season (my trichs dont go dormant in the winter up here)

Slower going cacti on the other hand I will only feed every 3 to 4 weeks.

I feed my lophos 1/2 strengh seasol every 2 weeks and 1/2 strengh Yates C&S fert every other 2 weeks.

I dont use slow release ferts (other than whats in the seals C&S mix I use) as I prefer to do it all myself.

Edited February 12, 2008 by AndyAmine.

[kakti]

The lack of spines on the newer growth is probably due to lack of a mature root-structure, so at this point the energy is going into forcing out growth and spines are a secondary thing. I think once the roots start to get a bit more mature and form a neat, nutrient-sucking ball, the spines will become as they were on the mother before cutting.

Hit the nail on the head