Soft Cactus After Watering

[mpetro]

I repotted my Cactus a few months ago. Soaked him for a while to kill any suspected root mealy bugs (found a white fuzzy on his roots). Then repotted and waited about 2 months until watering. Usually when I water him, he plumps up fat the next day and then returns to normal not long after. This time, I watered him, enough for the water to go out the drainage holes, and the next day he was soft instead of plump. He also became real loose in his soil like before I repotted him. It's been about 2 weeks since and he's still soft. He's also a lighter green color, which he has been since I soaked him a few months ago.

I think this means he needs more sunlight? Or because this happened the day after I watered him, I worry I overwatered? I watered him the same as I used to when he would plump up the next day. So it worries me

I didn't see any fuzzies on his roots this time when I moved him around a bit (because he got loose in the soil, he was easy to move). It's been glum and rainy recently, but we've had many sunny days the past few months for him to soak up. I'm thinking where my window is, the light isn't hitting him properly. I live in a small NYC apartment and the window only gets sunlight from a small section of open sky because the window faces the other side of the building. I tried buying a grow light, but have nowhere to plug it in because all my outlets are behind furniture and if I use a surge protector, the wire has to run across my bedroom floor and I'll trip on that for sure.

If he needs a grow light, are there any battery operated ones? I tried searching online but only see big and bulky plug ones. I don't know how I could even set up a battery grow light in my window sill... I was thinking one that sticks to the wall, but then the light would hit him from the side, not above.

I was thinking I could put him under my desk lamp and give him that regular LED bulb light? But then when would I put him there and for how long? I would have to take him out of the window sill, away from any sunlight he'd get there, in order to put him under my desk lamp. I worry taking him out of the window during daylight hours and giving him artificial light bulb light would hurt him more. But if I give him light at night, then he won't have any time in darkness (plus I need my lights off to fall asleep).

Here's a photo of him from when I soaked him:

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He looks mostly the same now, except he's soft when I poke his spines. He's also a lighter green than what the photo shows (but he was the same light green back then, too).

[Download]

Is there a reason you unpotted your cactus instead of just using insecticide? I imagine saturating the pot with insecticide solution would have done the trick but without damaging the roots by desoiling them and then soaking them in water where fungus and bacteria can attack the cacti.

Photos will help, but my money is unfortunately on rot.

[EdekaReweAldiLidl]

About the cause, the soil may be different before and after repotting. I also water my cacti thouroughly until water leaks out. How exactly did you repot? Maybe the soil you used now is worse than previously.

If it is salvagable, the best thing to do now is unpot it and remove all the soil and let the roots dry. See if anything looks black and if it stinks.

[abhikjha]

I guess you need to take him out of the pot and see if the roots are fine and healthy. If there is no problem with the body and if plant is unable to drink water, often the problem would be with roots. After unpotting, wash the roots with normal soapy water, keep it dry for few hours under fan, trim the black and unhealthy looking roots then soak the roots in 3:1 hydrogen peroxide solution (3 parts water, 1 part 3% hydrogen peroxide) for half hour, keep it dry again for at least a day.. then repot it in pure mineral mix (I normally use 100% pumice or perlite with gravels for all my plants) and don't water it for next 7-10 days. For quick healing of roots, you can use 1 tsp of bonemeal and also systematic fungicide to prevent any rotting in your new potting mix. Avoid watering it when it's overcast.

[greenknight]

Might have been better to add this on to the previous thread, so everyone could see how we got to this point - here's a link: http://www.cactiguide.com/forum/viewtop ... 29#p382529

Since cacti will cast off their fine feeder roots during a long drought, it's not surprising that that it would be slow to take up water at first. That it's still soft after 2 weeks is worrisome, though, it would be best to check the roots again, make sure the aren't rotting.

[mpetro]

I repotted him because I noticed a white fuzzy on his roots. Soaked him in soapy water, then hydrogen peroxide and water. Then I repotted him a few days later, then watered him a few months later (a few weeks ago).

My previous post: http://www.cactiguide.com/forum/viewtop ... 11&t=45846

Is it possible the soil is a bad batch? If so, how do I find out?

Each time I repot him, it's slightly different because I throw away the old mix. I try to put a bunch of the white rocks on the bottom and then I mix the white rocks with the dirt/soil mix, then I put some more white rocks on the top. These are the mixes I've been using:

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I took some photos today, it's real sunny out! It seems his bottom spines are not as squishy and the ones that were facing the sun. His top spines are the softest when I gently press them.

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I moved him around to see his roots without completely depotting him. I worry if I keep repotting him every few months, it will stress him out too much and make him weaker? Especially since summer is so close in NY.

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He still has some white around the top of his roots, I think on the same side as he did before I soaked him. Is this mealy bugs?
Is it possible the white stuff is from his roots touching the white rocks on that side?
Did I maybe not clean the plastic pot and mug enough to kill any mealy bugs (I washed it in soap and hydrogen peroxide)? Should I get a new pot, and if so what kind?

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[greenknight]

It would be better to get the different soil components uniformly mixed before you put them in the pot, but as long as they're fairly well mixed, no layer of pure gravel in the bottom, it should be okay.

What proportion of pumice gravel (that is pumice, right?) to potting soil did you use?

I zoomed in your photos and took a close look, I don't see anything that looks like mealy bugs. The washing you gave everything should have gotten rid of them. To be extra sure, you could give it a soaking in soap solution or systemic insecticide once you're sure it's taking up water.

Does the soil in the pot seem to be drying out? You could probe with a skewer or something, unless it's staying wet in the bottom of the pot there's nothing to worry about. If it's clearly taking up water there's no need to unpot it again. in that case, when it gets dry, give it another full watering.

If it's firming up slowly, then it's probably fine. It lost a lot of roots, and it's pretty dehydrated, so it isn't surprising if it takes a while to plump up. If you don't have a cool place to overwinter it, you need to give it a little water once a month or so over the winter to stop this from happening - not a full soaking, more like a couple tablespoons full.

[mpetro]

Yeah I mix the two mixes inside the mug and then pour it into the plastic cup while holding my Cactus in the middle. I would drop a few of the white rocks along the bottom, but they're too small to form an entire layer, they'd fall right through the drainage holes. And I put extra white rocks on the top because I think they look nicer.

His soil is definitely dry! Made a crunching sound when I moved my Cactus to see his roots. I didn't check too far down, but the top inch or so is dry for sure. Is the drier soil why he's looser in the pot? Because the soil isn't so tightly packed anymore?

Also should I water again now because his soil is dry (I'll check further down with my stick to make sure it's actually dry first) or wait until he hopefully gets more firm all over before watering again? Or maybe a few teaspoons only like you said for overwintering (even though it's nearly summer)?

I got an extension cord and am looking at these "angel ring" lights: https://www.etsy.com/listing/990575376/ ... phyto-grow

The seller says the sunshine yellow color is 3000k and the pink and white is 4500k. So if I get those, I would use those during the day in combination with sunlight from my window or should I move him away from the window when I use the lights? Or maybe only on cloudy days or later in the day when the sun is on the other side of my building?

[greenknight]

If it's dry down deep, that means he's taken up the water, and it's time to water again. Give a full watering in that case.

The top spines can be soft because they're still growing, don't worry about that.

Top dressing the pot with a layer of straight gravel is fine - it looks good and helps keep the soil stabilized so you don't wash holes when watering or splash dirt on the cactus.

3000k color temperature would be best. The description calls those "supplement" lights. I would use that kind of light along with the sun, start with it at its maximum height and gradually move it closer as the cactus gets used to the extra light. LEDs don't radiate heat, so there's little chance of burning, but best to play it safe anyway.

[Vingames1]

The white fuzzy you coulda thought was a mealy bug was most likely a brand new root

[greenknight]

The white fuzzy you coulda thought was a mealy bug was most likely a brand new root

I'm the one who thought it looked like mealy bugs - I've dealt with mealy bug infestations, I know what they look like. This was found during the dormant season, when the cactus hadn't been watered for a long time, not a time when roots would be growing. There wasn't just one, also "one or two smaller fuzz patches".

[nes]

Could it have gone into shock? Two months without any moisture might've caused the roots to desiccate.

[greenknight]

Not really shock, it's an adaptive response of cacti to lose fine feeder roots under drought stress. sometimes the entire root system is cast off. It costs the plant less to grow some new roots when moisture becomes available again than to use its reserves to keep all those roots alive when there's no water for them to take up.

Having mealy bugs, even just a few, costs more moisture and causes increased root loss.

[nes]

Thanks for sharing this knowledge. I've yet to deal with mealybugs but I'm sure I will have to sooner than later.