Cactus and Succulents forum: Lithops seedlings disappearing?.... maybe I can't count properly?

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Montreal, QC (Zone 5a)
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Rockcozy
Jul 28, 2020 8:39 AM CST
Hi there,
I've got some lithops seedlings on the go that I planted on July 11 (17 days ago). They are in terra cotta pots inside ziplock bag on a bright windowsill and ambient temp has been about 28-32°C (82-89F) daily highs and down to 20-25°C (65-77F) at night with withering humidity (ug, Montreal summer). Condensation in the bags has been pretty heavy and the terra cotta still dark/saturated so it's extremely moist inside. Three days ago I noticed some white filaments on the damp topdressing so I opened the bags, washed and dried them to get rid of any spores on the bags, spritzed the filaments away with a bit of rain water in a spray bottle, and sprinkled a tiny pinch of cinnamon on everything. Then I shut the bags again. So far I can't see any new mold growth.

Here's the weird thing though, on Saturday I counted 11 seedlings (out of 20 seeds, pretty good germination rate so far. ) Today (three days later) I can only count 10 and one is super tiny (new) so somehow I overcounted by 2 on Saturday or else two have totally disappeared.... I didn't shift the topdressing to see if they collapsed down into a gap because I'm not sure exactly where they were and don't want to disturb the rest.

Also, at least two look a bit lighter green and maybe limp. Are these damping off, if so should I remove them to protect the others? Is there anything else I can do? I think my initial setup was too damp.

I did sterilize the potting mix in the microwave before planting but I didn't use any fungicide because the one I've seen most recommended online is apparently not legal for sale in Canada.

Any advice would be much appreciated. Many thanks
Name: Eric
Wisconsin (Zone 4b)
Cactus and Succulents Plant and/or Seed Trader
Hallow
Jul 28, 2020 10:14 AM CST
I live in a nearly identical environment as you do. Growing succulents in this environment is like trying to grow a maple tree in the desert. Rolling my eyes. with that in mind. Humidity.... I be had lithops go 11mo. Without a watering and I can assume there simply living off the humidity. There little extremest. What I would do is uncover them give them good air circulation and mist well when you notice the soil dry. Put them on a window sill that gets morning sun.
Montreal, QC (Zone 5a)
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Rockcozy
Jul 28, 2020 11:47 AM CST
Hallow said:I live in a nearly identical environment as you do. Growing succulents in this environment is like trying to grow a maple tree in the desert. Rolling my eyes. with that in mind. Humidity.... I be had lithops go 11mo. Without a watering and I can assume there simply living off the humidity. There little extremest. What I would do is uncover them give them good air circulation and mist well when you notice the soil dry. Put them on a window sill that gets morning sun.


OK I suppose you're right, I'll vent the bag and hope for the best. I can't see the soil on account of the pebbles but i'll watch the pots. Thank you!
Name: Baja
Baja California (Zone 11b)
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Baja_Costero
Jul 28, 2020 1:06 PM CST

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When you start with really tiny seeds, and Lithops seeds are on the tiny side, hygiene is really important. They will need to be in a warm, humid environment for months, and closed systems like that are a perfect breeding ground for all sorts of organisms other than Lithops. So you don't want to be opening and closing and washing the bags and spritzing and putting cinnamon in there. All that does is increase the chances your cacti will not make it to a point where they can do well with less moisture in the soil.

Set up the whole thing clean and carefully from the beginning. That means using new pots, or thoroughly bleaching the old ones if you use them. Bleach the top dressing if it's not already clean, but don't put anything on top of the seeds if they're really small, like Lithops seeds. Use clean (purified) water to wet the soil when you set things up. Cooking the soil before use, if you did it carefully, was a good idea. Use a new bag or bleach the inside of an old one. After sowing, leave the lid on tight, or the bag closed tight, indefinitely. Don't open it up to check out the scene. Don't open it at all until you're ready to get the pot out and start gradually ramping down the humidity. Make sure it's in a bright place (max out the light if it will be indoors) and monitor carefully through the plastic.

But what's done is done, and I understand your goal is to keep your baby plants alive. Your challenge at this point, if you want your baby seedlings to survive, is to leave them protected only as long as necessary, and then work on getting them out of the bags and gradually allow the humidity to go down (spritzing with water using a fine spray every so often so it's not a precipitous drop to zero). I would wait until they are a few mm and have a reasonable succulent reservoir. Jumping the gun will require you to provide much more attentive care. When you take them out from under plastic, you need to be really really careful how you water them (fine mist from above is best at first) so that you don't hit any seedling with a big drop of water and uproot it completely. I like to water from below (instructions upon request).
[Last edited by Baja_Costero - Jul 28, 2020 1:10 PM (+)]
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Montreal, QC (Zone 5a)
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Rockcozy
Jul 28, 2020 1:58 PM CST
Wow thank you @baja_Costero this is amazingly helpful. Thank you. Humidity here is >50% at ~ 85° every day so things dry out very slowly, I'll try to find a happy medium with attentive spritzing now that I've opened them up already. This requirement for long periods of high humidity is totally unlike their natural environment, I wonder how it works in nature? I ordered a copy of Florent's Namaqualand book and it arrived yesterday, maybe something in there will give some insight.

Thank you!!
Name: Baja
Baja California (Zone 11b)
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Baja_Costero
Jul 28, 2020 6:50 PM CST

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There's lots of insight in that Namaqualand book, though I didn't read much about Lithops. I think the situation in habitat is all about location, when it comes to seedling survival. Various factors come together to allow a very small number of seedlings (relative to the number of seeds) to survive to adulthood.

The humidity you describe is lower than our annual average (80%), and our nightly humidity is routinely over 90%. I suppose high humidity would tend to slow down evaporation, and it certainly does compared to the alternative. But in the presence of strong light, evaporation is pretty efficient even here.

The key parameters dictating seedling survival in habitat, at least as it relates to water, are (1) the initial duration of continuously moist soil (how long the soil remains wet after germination), which is often a seasonal thing; and (2) the duration of the first drought (how long the soil goes dry before it becomes moist again). Basically how long do seedlings have to get a running start, and how big is the first hurdle after that. These things can be studied retrospectively because of detailed weather records.

Our experience in cultivation is somewhat detached from the harsh reality of habitat. I don't know about Lithops, but the succulents that grow wild around here (Mammillaria, Ferocactus, Dudleya, Agave) grow much much slower in the wild than they do given proper nursery care. Maybe 5-10 fold slower, depending on the location. I think these plants prioritize survival over fast growth because of their evolutionary selection in dry or seasonally dry climates.
[Last edited by Baja_Costero - Jul 28, 2020 7:20 PM (+)]
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Name: Eric
Wisconsin (Zone 4b)
Cactus and Succulents Plant and/or Seed Trader
Hallow
Jul 29, 2020 12:14 AM CST
Baja_Costero said:There's lots of insight in that Namaqualand book, though I didn't read much about Lithops. I think the situation in habitat is all about location, when it comes to seedling survival. Various factors come together to allow a very small number of seedlings (relative to the number of seeds) to survive to adulthood.

The humidity you describe is lower than our annual average (80%), and our nightly humidity is routinely over 90%. I suppose high humidity would tend to slow down evaporation, and it certainly does compared to the alternative. But in the presence of strong light, evaporation is pretty efficient even here.

The key parameters dictating seedling survival in habitat, at least as it relates to water, are (1) the initial duration of continuously moist soil (how long the soil remains wet after germination), which is often a seasonal thing; and (2) the duration of the first drought (how long the soil goes dry before it becomes moist again). Basically how long do seedlings have to get a running start, and how big is the first hurdle after that. These things can be studied retrospectively because of detailed weather records.

Our experience in cultivation is somewhat detached from the harsh reality of habitat. I don't know about Lithops, but the succulents that grow wild around here (Mammillaria, Ferocactus, Dudleya, Agave) grow much much slower in the wild than they do given proper nursery care. Maybe 5-10 fold slower, depending on the location. I think these plants prioritize survival over fast growth because of their evolutionary selection in dry or seasonally dry climates.
a lot does depend on your environmental conditions. I took a screenshot of my weather here now. This is a very common temp and humidity.


Thumb of 2020-07-29/Hallow/c1d6b3

There a lot of different conditions that can affect seedling growth. Growing medium is a huge factor. On a lot of seed and plant growing I am self taught. For example when I start seedlings I use a good airy cactus mix. That would probably make the professional plant people cringe. But, it gives higher nutrients and holds moisture well for them to get a strong start. I used to have major problems damping off. Until I increased air circulation and put them good sunlight. Fungus hates moving air, dryness, and sun. I typically keep them in that media for about a year or until there large enough to move without hurting them.
You're correct in saying these little guys are built for survival very slow growth. In a sense they only sustain themselves. You only want them to grow 1 set of leaves a year. But in order for them to grow that new set of leaves for long term care they also must "use" last seasons new leaves. During a rain in nature they suck up all the moisture as fast as they can to the point of watered to much they can pop open. Also with These they store water and nutrients in there leaves to grow next seasons leaf. I have one growing now you can see old growth drying at the same rate the new growth is growing. It's fun to watch. But if you water during this time. The old leaves that are drying will fill up like balloons and hold water. That water in the old leaves will cause it to rot.
[Last edited by Hallow - Jul 29, 2020 5:20 AM (+)]
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Name: Eric
Wisconsin (Zone 4b)
Cactus and Succulents Plant and/or Seed Trader
Hallow
Jul 29, 2020 5:38 AM CST
Thumb of 2020-07-29/Hallow/578281

This isn't a lithops but it's a plant that needs the same type of care. It part way through growing it's new set of leaves. You can see the oldest set of leaves drying up. It's useing stored energy to grow the new leaves. The oldest set of leaves were once the same size as the largest ones. Lithops do the same thing.
Name: Eric
Wisconsin (Zone 4b)
Cactus and Succulents Plant and/or Seed Trader
Hallow
Jul 29, 2020 10:20 AM CST
Thumb of 2020-07-29/Hallow/6eaa76

Here's a lesson on Wisconsin fungus. Hahaha. This plant I water very sparingly. It's kept outdoors in summer time. This plant should be getting more sunlight and it's obviously not getting enough air circulation. Dead still humid air is common here in summer. I moved this plant to full sun to cook off the mushrooms. Thing's like damping off is a type of fungus/mold I am in constant battle will. I am sure you have the same type of fungus problem in Montreal. Sun and air movement is your best friend when it comes to growing any succulents in our climate.
Montreal, QC (Zone 5a)
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Rockcozy
Aug 3, 2020 9:40 PM CST
Thanks @hallow this is very useful ! Our weather conditions are indeed similar although we haven't been down to 66°F in a while... when we do, freezing won't be far behind.

Considering I already have a mold issue I decided to ditch the bags and I'm misting the top of the pots a few times a day. I think the seven remaining seedlings are already stretching and ordered a grow light to supplement the light indirectly, before moving them to a sunnier window. I'm not sure if I'll be able to save the seedlings, might have to get chalked up to a practice round but I can't complain, I've learned a lot.

My older, store bought Lithops just finished absorbing old leaves, got repotted, got watered, doesn't seem to care. I guess it will be a while before I can tell if it's settled in ok or not. My local succulent nursery sells cactus/succulent soil and also a special lithops mix that is even more rock, mixed pumice, it looks nice.

Is that a Pleiospilos in aqua aquarium sand??

Thanks again @baja_costero for recommending that Grenier book, I made a little pot today inspired by the conophytums on the cover. Thinking about doing more with specific plants in mind. Running out of sunshine in my house though.

Thumb of 2020-08-04/Rockcozy/af0a7e

Name: Eric
Wisconsin (Zone 4b)
Cactus and Succulents Plant and/or Seed Trader
Hallow
Aug 4, 2020 11:31 PM CST
Rockcozy said:Thanks @hallow this is very useful ! Our weather conditions are indeed similar although we haven't been down to 66°F in a while... when we do, freezing won't be far behind.

Considering I already have a mold issue I decided to ditch the bags and I'm misting the top of the pots a few times a day. I think the seven remaining seedlings are already stretching and ordered a grow light to supplement the light indirectly, before moving them to a sunnier window. I'm not sure if I'll be able to save the seedlings, might have to get chalked up to a practice round but I can't complain, I've learned a lot.

My older, store bought Lithops just finished absorbing old leaves, got repotted, got watered, doesn't seem to care. I guess it will be a while before I can tell if it's settled in ok or not. My local succulent nursery sells cactus/succulent soil and also a special lithops mix that is even more rock, mixed pumice, it looks nice.

Is that a Pleiospilos in aqua aquarium sand??

Thanks again @baja_costero for recommending that Grenier book, I made a little pot today inspired by the conophytums on the cover. Thinking about doing more with specific plants in mind. Running out of sunshine in my house though.

Thumb of 2020-08-04/Rockcozy/af0a7e

I live in a cool and damp microclimate of the great lakes. Even a 10 min car ride in anyother direction its always 15°f warmer and the air is dryer. It's like a bubble you drive in and out of. When you drive into our out of the bubble your car windows fog up and it feels like you're driving into or out of an air conditioned building. Not the best place for most succulents. You just need to adapt to your environment in order to grow them well.
The sand is only for decoration. Just have a thin layer of it on top.

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