Rot or Not? Please help

[CoolestGravy]

I picked up this pincushion cacti over the weekend. I believe she was living in a greenhouse before. I found that she came with these concerning looking spots.

My thoughts started with rot. But I poked the areas with a chop stick and they're really firm. What looks like a bit of goo on the spines is hard candy like.

Unless i have to perform emergency surgery, I will be putting her in better soil and in terracotta come spring. I'll chop and prop if I must, but it would be lovely to not have to.

[FredBW]

You didn't say where you are. But you are talking "come spring". So that must mean it's winter where you are
I can't tell what the spots are from your picture. But if it were mine I believe I would just unpot it. If it's damp let it dry out. If there is actually rot it should be evident at the base and the roots. It looks more like some kind of injury to me but it's hard to tell from the pictures.
If it's dry thats OK. If you can get the soil off the roots without too much trouble put it in fresh cactus soil. If it's rock hard peat,might want to wait till spring when you can soak it and clean that stuff off. And if it is rock hard dry soil odds are extremely high it isn't rot.
Just my opinion

[CoolestGravy]

Sorry, I'm in Utah and it is winter. This one came with wet soil. My residence is surrounded by neighboring trees that don't give me enough natural light, so my cacti are full time under a grow light.

What's your personal opinion on repoting in my circumstances? Do I really need to worry about winter dormancy? If you were to repot, would you wait for the soil to dry out or should I dunk the rootball in water to gently remove the soil?

I understand any advice is subjective and that regardless of what I'm told, I'm responsible for my own decisions.

[Steve Johnson]

First of all, please see this:

https://www.cactiguide.com/forum/viewtopic.php?t=43819

If you were to repot, would you wait for the soil to dry out or should I dunk the rootball in water to gently remove the soil?

I'd get a container of water and do the following:

• Swish the root ball around to dislodge the soil from the roots.

• Use a blunt instrument like a q-tip handle, knitting needle, etc. and "tease" the soil out of the roots.

• If the water is dirty, dump it out and fill the container up with fresh water. Swish and tease again. Be sure to gently dig the soil out from the spot right under the base. Keep at it until the roots are as squeaky-clean as possible. If some of them come off in the process, don't worry -- your cactus will grow new roots.

With regard to potting medium, my default recommendation is a mix of 50% pumice and 50% soil with minimal organic materials. You could go a bit leaner -- 60-70% pumice and 30-40% soil. When the roots are clean, let them dry out completely and repot in fresh, dry mix. I keep my collection outdoors 365 days a year, so if I had to repot any cacti now, I wouldn't water them until the growing season begins in the spring. Since you have your plants indoors under grow lights (and assuming that night temperatures in the house are at least 55), I think you'd be fine giving your cactus some water every 2-3 weeks after repotting.

I agree with Fred -- the spots look like mechanical damage (like getting poked by spines from another cactus), not rot. However, you should still keep an eye on the situation. Also, look for the possible presence of stem and/or root mealybugs. If you see them, let me know, and I can give you some guidance. With regard to terracotta, here's something for your consideration:

https://www.cactiguide.com/forum/viewtopic.php?t=45833

By the way, have you been fertilizing your cacti? If so, I'd like to discuss the fertilizer situation with you.

[CoolestGravy]

Alright, I'll get some terracotta and good soil together. I appreciate all of the advice from both of you. And even if the roots all look great, I'll be sure to keep a close eye on the concerning spots. Your assessments of what I can show are heartening. (Sorry, I had to really bring the quality down, for the website to take the photo)

I've never repotted anything with this sort of weight and dimension before. I assume I'm going to want to use supports, but I'll take any advice on this I can get. I'm admittedly nervous about keeping it stable.

I haven't used fertilizer, but I'm interested. Bring on any advice you want to share.

[Steve Johnson]

Mass-produced terracotta pots in the US are made of porous clay, so you might want to rethink terracotta for the reason I explained in the link I just gave you. Here it is again:

https://www.cactiguide.com/forum/viewtopic.php?t=45833

[CoolestGravy]

I goofed up and I can't figure out how to delete a comment. Please disregard this particular comment and move on to the next.

[CoolestGravy]

Well that's a pretty hard left turn for me, ha ha. It gives me a lot to think about. The pot drying out the soil is something I've always enjoyed about terracotta. I suppose I need to try harder to figure out what my cacti actually look like when they're thirsty. I have this Fairy Castle that has been doing seemingly great with me for almost a year now (notable growth that's not etiolation, thank goodness) on a watering schedule of every 2 weeks. So I'll also need to give your soil mix more consideration, I'd been using Fertilome.

I'm still eager to hear any advise on repotting something this top heavy, and fertilizer. That being said, if you've had enough of me, yall have been a big help and I really appreciate it.

[jerrytheplater]

Don't worry about your plant being top heavy. Once you get the roots free and dried out as Steve said above, (and dried out can mean up to two-three weeks if needed.). Again, after the roots are dried out and you repot in a mineral based mix, the mix will hold your plant.

From what I can see in the last photo, it looks like your plant is potted with the very bottom of the cactus body above the potting mix. That can be planted deeper by applying a top dressing of straight coarse gravel around the base of the plant. I have a few cacti with a long corky stem that is about 3-4" long. I have it potted in a deep pot with about 3-4" of gravel on top of the planting mix.

Take a photo of your plant once you have the roots cleaned off from the present potting mix for your own records and to show us.

And don't worry about asking questions. How else are you going to learn, except by killing a few plants?-which we all have done.

As far as fertilizer-plants need to eat too. You won't survive very long on a diet of water only. Same for your plants.

[CoolestGravy]

Thanks Jerry!

It's been a very long time since I've been on a proper forum and I'm starting to remember my manners. I can bring my potting and fertilizer questions to the appropriate areas of the website.

[Steve Johnson]

One of the great things about this forum is the ability to learn from each other. And we're a friendly bunch, so inexperienced growers shouldn't hesitate to seek out advice here. Same applies to members who are new to the forum -- these are the editor icon buttons:

Editor_icons.jpg (13.6 KiB) Viewed 1864 times

Edit post (1), Delete post (2), Report this post (3), Warn user (4), Information (5), and Reply with quote (6). I don't know if "Warn user" and "Information" are just for the moderators (I'm one of them, by the way), but I'm pretty sure that all members can delete their own posts if they want to.

I learned a lot about fertilizers from our horticulturalist-in-residence MikeInOz (you'll see some of his work here), so lesson #1 is knowing how to evaluate fertilizers based on their guaranteed analysis. This example comes from the General Hydroponics FloraMicro 5-0-1 and FloraBloom 0-5-4 liquid ferts I started using last spring:

FloraMicro-FloraBloom.jpg (83.55 KiB) Viewed 1864 times

If you post a photo of the Fertilome's guaranteed analysis, I'll give you an evaluation with comments. Also, please let me know about how often you fertilize and how much you apply per feeding. I believe that Fertilome is water soluble, so if that's the case, what we're looking for here is your dilution rate (1/4 tsp. per gallon, 1/2 tsp. per gallon, etc.).

[CoolestGravy]

Point of clarification. I've not used fertilizer at all yet. I've been using Fertilome's cactus soil, sorry for the confusion.

I've been interested in fertilizer, but I've been nervous about starting anything because I've read that succulents can be really sensitive to it. That's everything I know about fertilizer so far. I know I need to read more for myself, but I'll be glad to take all the info you're willing to share.

[MikeInOz]

I've read that succulents can be really sensitive to it.

They are probably less sensitive to dissolved salts than most plants because they come from areas which are not heavily leached by rain. Most of the sensitive plant species come from soils that are always moist or places were there is plenty of rain. Too much nitrogen is usually the main problem.

[Steve Johnson]

Okay, this'll be a good discussion for you...

Cacti and succulents aren't sensitive to fertilizers in general, but they are sensitive to the wrong ones. I'll explain what we mean by that:

• The "Big Three" major nutrients are nitrogen (N), phosphorus (P), and potassium (K).

• Fert manufacturers in the US report P as P2O5 and K as K2O (that is what you'll see in the label's guaranteed analysis). While the oxygen in P2O5 and K2O supports the plant's overall health, it has no nutrient value, so all we're concerned about are the actual amounts of P and K going to the plant. %P2O5 x 0.436 = %P, and %K2O x 0.83 = %K.

• The ratio of N, P, and K tells us if a fert is well-balanced or not. Contrary to what you may have heard or read elsewhere (and I fell for this before Mike educated me on the matter) -- if a fert's N, P, and K numbers are the same (5-5-5 and 7-7-7, for example), it is not well-balanced. The basic "rule of thumb" -- P lower than N, K higher than both.

With NPK ratios, N is always a constant of 1, so the variables are P with an acceptable range of 0.25-0.35, and K with an acceptable range of 1.1-1.7. P is the biggest problem when it's too high because anything above 0.35 per feeding will eventually inhibit root growth, stem growth, and flowering over time. When you look into different fertilizers, you can easily calculate their ratios by doing this:

• %P/%N = the number for the P side of the ratio.

• %K/%N = the number for the K side of the ratio.

The General Hydroponics FloraMicro and FloraBloom give me a combined NPK number of 5-5-5. Now we'll go through the math. 5% P2O5 x .436 = 2.18% P and 5% K2O x .83 = 4.15% K, so the true NPK number is 5-2.18-4.15. Next, turn it into a ratio -- 2.18% P/5% N = 0.44 on the P side of the ratio. Too high. 4.15% K/5% N = 0.83 on the K side of the ratio. Too low. I corrected the imbalance by adding the right amounts of ammonium sulfate and potassium sulfate.

After investigating a lot of "off the shelf" fertilizers, I have yet to see one that gets the NPK balance right for cacti and succulents. However, there's a lot to be said for the General Hydroponics ferts I'm using, so if you're willing to go through a few extra steps, you'll need the following:

• A digital scale measuring down to .01 grams. Not expensive, and you can find a good one here:
  
  https://www.homesciencetools.com/produc ... g-x-001-g/
  
  Way better than the cheapo scales I found on Amazon.

• Ammonium sulfate and potassium sulfate in powder form. Easily available on Amazon and eBay.

From there I can give you the instructions for making an ammonium sulfate-potassium sulfate stock solution, and a recipe with the right amounts of the General Hydroponics ferts and stock solution going into your watering solution.

I checked out the Fertilome cactus soil, and I think it has fertilizer "baked in". Even if it doesn't, the ingredients (Canadian sphagnum peat moss, horticultural perlite, granite sand, dolomitic limestone, calcitic limestone) were enough to tell me that you'll be better off with the mix I'm recommending.

I've read that succulents can be really sensitive to it.

They are probably less sensitive to dissolved salts than most plants because they come from areas which are not heavily leached by rain. Most of the sensitive plant species come from soils that are always moist or places were there is plenty of rain. Too much nitrogen is usually the main problem.

Mike makes a good point about the high N problem. Dilution = dosage, so what I have in mind will give your cacti the right dosage of N per feeding.

[CoolestGravy]

This place is so much better than reddit. It almost makes me feel emotions again. You guys are wonderful.

It might take me a sec to get everything together on this, but I'll be commenting on this post as soon as I do. Otherwise, you might see another post from me about a different cacti.