Outdoor cactus growing advice?

[Plant Pimp]

Since the weather finally started to warm up here, I moved some of my small cacti outside to get some more light. I put them in a 3 shelf mini greenhouse with an empty seed tray on the top shelf so they don't get full sun down on the second shelf. Many of them went from being plump and turgid to being soft and wrinkly. One even started to turn purple on one side. I'm especially worried about a 4 month old graft. Would the wrinkling be just form water loss? It only gets to about 20C in the afternoon and 10C at night. I'm not sure what the temp in the mini greenhouse gets up to in the day. I left the door about 1/4 open at the top so some humidity could escape. Should I worry about these and bring them back in or just start watering more often? Could the 10C nights be causing this? If anyone could relate some of their experince it would be helpful.

Thanks!

[Evil Genius]

Mmh, the color change to red indicates stress. I think "red" means too much light. Allegedly it doesnt kill the seedlings but i wouldnt bet on this. Take them to a shady place where you can control the climate. Seedlings aren´t strong enough to stand full sunlight. I would wait untill they are in their second year! bye Eg

[planthelper]

yes, like eg say's....

you have to graduatly get the cacti used to there new enviroment.

cacti can very easely get sunburn, if they haven't been used to direct sunlight.

act quickly, and give them far more shade again.

put them so they only get some direct morning sun.

the glasshouse type thing, is not good for them, now that the skin of your cacti got damaged, the humidety of the glasshouse might cause some rot, starting at those damaged areas.

they got limp because suddenly they have to deal with far more evaporation, so keep the watering up a bit, but don't go overboard, in other words avoid soggy soil conditions.

but make sure your potting mix continues to hold some of the moisture, what i mean is, that over winter your potting mix probably became so dry, that it is now very hard to re wet it (hydrophobic). so use a saucer or a pot and emerge the pots for an extended periode of time, or even re pot with fresh potting mix.

to be sure what is going on, you take the plants out of the pots and inspect the soil and root enviroment.

maybe you will find, the soil very dry although you thought you watered enough!

i don't think the 10 deg C are too cold for your cacti, but sure lophs will like it wamer, but pedros get much colder in south america.

[Plant Pimp]

Thanks for the advice!

I brought the little ones back inside to recover. Maybe I'll put them in a spot that only gets direct sunlight from 6:30am to 10:30 am and move it a foot a week increasing the time in the direct light. I'll try one good watering from the bottom up, if the top gets wet, than the soil must be ok. I don't really want to dig them up and chance breaking roots. I'll try the little ones out doors next summer.

Would they be better off without the plastic covering of the mini greenhouse? Today was as hot as it gets here (~25C). I'm not sure which is the better trade off, low humidity, lower temps or higher humidity, higher temps? I guess they probably like dry heat, but that won't be found around here.

[nothinghead]

Hi Plant Pimp, I had similar problems when I first got one of those small 3-tier greenhouses resulting in some severe sun damage. I did not realise how hot those little greenhouses can get and I think the high temperature, paired with humidity and direct sun (through the clear plastic), all exacerbate the intense conditions which the plants (especially coming out of winter) are not used to. It sounds like you did not "harden" your plants off, I did not either but have since learned the importance of changing conditions for your plants slowly and gradually. I agree with EG's and PH's advice on getting the plants into shade so they can recover.

I found those tiered greenhouses provided conditions which were too intense for my cacti, so I sewed some shadecloth together as a "wrapping" for the greenhouse. Now the plants enjoy an evenly distributed amount of diffused sun, the greenhouse does not get overly hot, while still being considerably warmer than outside of it, and the layer of shadecloth has provided excellent conditions for germinating seed. It's easy to do and really creates a good environment for cultivating cacti.

[SaBReT00tH]

hey plant pimp,

I know exactly what you mean. My beautiful plump lophs have shrunk, turned saggy and SQUISHY!! Thought it might've been rot but I don't think it is, it's just some kind of effect from the cold (even though they're in the garage), and my pereskiopsis loph graft is lookin a little purple too. I think it's just best to leave them until summer and hopefully they'll return to their usual happy selves then.