Howard - This was a pretty big concern for me too. I mitigated this by providing nearly the exact same light intensity under lights as my on my rooftop. You can see the intensity in PAR DLI in my graph below.

Through this whole transition, I only burned one plant slightly - just two leaf tips on my Gasteria pillansii. With healthy plants, I think there is more time for 'warning signs' to show up before the point of burning damage if you change your setup slowly.

Having light meters and a data logger really helped me quantitatively calculate everything to have a seamless transition between outdoors and indoors. That was the basis for # lights, spacing, and plant positioning. Here is a very messy sketch I used as I was measuring my relative light distribution of my initial setup (in foot-candles):

That's the brightest place in my home until all the leaves drop. I'm really hoping my living room gets a lot better then, since my loft will be stuck with decreasing light as the snow comes and covers my skylight.

The collection of maps below shows that in zone 6a (by the Great Lakes), light in December outside is more like partial to full shade, which is kind of scary.

As for switching day and night, this is a brilliant idea and would cut down electricity costs by ~1/3 because of time of use pricing. If I had everything in the basement, this would be the best option.

Agreed that there is still lots of light outside and I have many plants outside there still. =)

Thanks mayo...gathering any info I can to improve on previous year, soon the 'great exodus' will start...If the weather stayed same as this week so far, for another month, that would be great :)

I switched day to night exactly for that reason. I believe there was quite a saving on electricity (I should ask you to calculate it, lol) and the plants didn't suffer at all. I didn't see any difference between ones in basement and ones by the window. My lights were mix of fluoro and cfl's.

Rina - I could use weather that was about 22C instead of 27C, but the light I am quite happy with!

How many watts of lighting are you using? It works out to roughly $0.038 per watt per day, in your case.

Huh, never added it up - I know I should...denial! Spending too much time and money on succulents...

How much is this costing?
I have about 70 succulents ranging from 2-3", and I'm wondering if I need to bring them in for the winter (moving to TX next month).

Warmer in TX than Ontario, Canada...you probably don't have to bring many in. I have quite a few more plants and the winter is long.

Kevin, I'm a bit thick skulled today and I'm not clear as to what you are representing with the 'cyan' coloured graph and your hand-written sketch. Not sure what is represented along the x/y axis. Are the numbers inside the box recordings of lumens at different distance from object? I will definitely do some more experimenting this winter! Thanks, Howard

I'm going to need the legend for that chart as well, Kevin. I have an identical winter set-up--just 6500k T5HOs. One shelf is on for 14 hours and the haworthia/gasteria shelf is on for 10 hours, everyone is about 3 inches from the bulbs. (H. tesselata is so shy you can turn it red just by sneezing at it. I found that putting it farther away will stretch it quickly so I decided I'd rather it is red all winter than have it transform into a giraffe).

It never occurred to me to shorten the period during the coldest months, Howard. Thanks for the idea--that's probably going to help my plants that are natives of higher latitudes. Not so much the equatorial ones. Does it affect blooming, simulating shorter days this way?

I use blocks of wood from my shop to individually adjust the distance of the pots since they and the plants are not all the same height.

Thanks for this informative thread.

Pagan

The lighting discussion is beyond me, but the plant pictures are very pretty ;)

SucculentCity - Most single T5HO light fixtures I see are around $40-45 each, including bulbs. So depending on your space and needs, it goes up from there.

Howard - Agreed and wish the labels were on the cyan graph's axes as well. Probably it makes a lot more sense seeing the readings for a shorter period - such as a single day on my roof (from a single spot):

DLI is is measured in mol/m^2/day. Which is a pretty absurd sounding unit. It is a measure of how many photons hit a square meter of space in a day. Photosynthetic Active Radiation (PAR) takes this further and only considers photons that hit and are within the wavelengths of light plants use (400-700nm purple to red).

As a comparison, here is the readings for a day under my lights. At noon, my timer shuts off the lights for two hours to save on electricity/heat generated. This shows how the ambient light is quite low in that spot:

Getting to your question, this is different than lumens, which is the intensity of visible light emitted from a source. My setup is ~30,000 lumens. In my opinion, this is helpful as a general figure for comparing light bulbs, but does not consider the efficiency and light distribution of the reflector used.

Not having a reflector roughly would half your light output. Difference between a good reflector and a bad one could be 30% or so as well. Unfortunately, most fixtures we can easily buy do not have the necessary photometric data. For industrial manufacturers, they give all the details/model so you can exactly design your lighting configuration.

In my messy black and white hand sketch, that was the numbers from my lux meter to map out where the brighest and darkest spots on my setup were located. Most importantly, I used that to figure out where to put my Haworthias.

Glad to hear you'll do some experimenting!

Pagan - My H. tessellata is the same... either it looks like it's going to stretch like crazy or it's dark brown from so much light.

Yes, some plants flower seasonally based on the day length. Somewhere I found a nice graph showing the variation of day length vs. latitude. In Ontario, we have a much bigger variation in summer/winter day length than in South Africa (where Mesembs are from).

I think most succulents do it based on growing conditions or day length. I don't think many do it based on differential between day and night temperatures, but I could be wrong.

Please post a photo of your setup if you have one. =)

Suivezmoi - Thanks!! Feel free to add anything you think would be helpful too. Sometimes even the simpler things are important and are easy to miss.

So mol/m^2/day is lux (luminosity per unit area) measured over time (in this case, a day)? Does this mean you have an actual table of how much light each plant needs in a day and measure your light output thusly so you can adjust your lighting and arrange your pots according to that table? If you have it, I want it! lol

My set up is so far just this:

Pagan

Pagan - Yes, mol/m^2/day is how much light is received in an area in a day. It's better than an instantaneous measurement such as lumens because most succulents act as 'sun collectors' during the day and complete photosynthesis at night with that stored energy.

I did make a table of light requirements for some of my plants, but it was limited and I never bothered updating it.

There is a very interesting chart of DLI requirements based on actual experiments by Perdue University. See Page #5 of this white paper. Not many succulents there, but Schlumbergera is listed with the following details: (I consider shade DLI to be under 8.)

• DLI of 4 - Minimum acceptable quality
• DLI of 6 to 8 - Good quality
• DLI of 10 to 16 - High quality
• DLI of 16 to 30 - High quality, but requires cool temperatures

This was one set of data that really got me thinking about light requirements for plants. For the longest time I thought Schlumbergera were 'shade loving plants'. But actually they love much brighter light than that! Once I moved mine to a 10 DLI location, they started to have all sorts of new growth.

I realized that there is such a big misconception of how much lights plant require. Most of the guides out there are totally skewed! The only truly reliable information is 1. Botanical studies or 2. Actual experts in the field. For what it's worth, I consider you guys here as actual experts. =)

Looks like you will have a really nice setup there! Shelves look nice and sturdy. Before you do all the painting of the boards, I would test and find out the temperatures you get. I had add a fan during the daytime to ensure the room wouldn't get incredibly hot.

If you can manage temperatures around 20C or so, I think that would be pretty ideal. My temperatures are peaking at 40C on super hot days, which isn't as productive for growth as I would like.

Hi ewwmayo

Hi all, im new to this forum and im staying in singapore. Relatively hot and humid all year round. Just started keeping haworthia few months back under 4 x 39w t5 ho. The h. Cooperi , truncata and retusa all turning brown, dry and dull. I used a timer to keep the lights on from 7am to 6pm and the plants are all 2" to 3" off from the light . My lightmeter shows 300 to 400 x100 lux directly under and center of the light and further to the end of the t5 tube or at the base of my shelving without and wood block to increase the height, i could only get 100 - 150 x100lux . Temperature hovering between 30 to 32 degrees celsius and i watered them once a week

My question?

How to prevent the haworthia from turning green to brown? Move them further to the edges? But that would only generate about 80 to 90 x100 lux only and im worried that would be insufficient for them.

Based on your chart, where should the harworthia be placed?

Hope some experts here can advice. Quite dishearted to see truncata turning brownish red and the retusa colors turning dull

I answered in your other nearly identical post on the other thread: [Light for Haworthias[(https://www.houzz.com/discussions/light-for-haworthias-dsvw-vd~3770308). =)

Hey ewwmayo.. can you enlighten me based on your foot candles chart, where are your haworthias mostly located in? Thx a million!

Desmond - I have three setups for grow lights now. The primary one I only had a few Haworthia in. The second and third is pretty much all Haworthia.

My second and third setups are currently around 750-1500 foot candles because I'm rooting a large number of new plants. Usually they go up to 2000 fc when established.

I see thanks ewwmayo. So i presume the haworthias are at their comfort level from 750 to 1500 fc right?

Desmond - 750 to 1500 fc is low, as I said I am establishing new plants and do not want to stress them too much.

I don't really understand what 'comfort level' means?

Ewwmayo

Comfort level as in the fc level your current haworthias is in, minus the yet to establish ones.. and they still maintain their green

Desmond - Depends on the species. Personally, I don't keep many that green. It's easier to show a photo:

Nice haworthia gang you have there.. wonderful

Hi all,

Sorry if this was mentioned elsewhere, but many state that a dormant period is necessary for cacti and other succulents, often during winter. How does growing under lights during winter affect this required period? People say to water once or twice per month, but I assume you are still watering every few days under these lights.

Is the period of dormancy required? I imagine it depends on the specific species. Is there any danger to growing cacti under lights and watering and fertilizing as I do when outside in the summer? I do, as recommended here, have the hours per day of lighting approximately matched to sunrise/sunset, but shouldn't intensity of light also be matched (if possible) to winter month intensity?

My original goal with lights was to prevent some of the etioliation I was seeing in winter, but now just thinking about this dormancy thing. Unfortunately don't have a cool basement/garage so temperatures stay warm in the apt.

As always, thanks for the help.

Volcoff - You ask a lot of good questions. =)

Dormancy is very species specific and there is no blanket genus-wide statement that covers all. It does depends on exactly what you are growing, yes.

Most succulents are opportunistic growers, meaning they will grow any time the conditions are favourable. In general, most succulents do not require dormancy period. If you have good growing conditions, then it's nice to grow year long and keep the action going! Nearly my entire collection is actively growing right now.

The winter danger is over watering or if your pots take too long to dry out. I am still watering every 6 days in the winter under lights. Watering frequency is highly dependent on temperature so be mindful of that. Continuous airflow is also highly recommended for indoor winter growing.

No issue with fertilizing as you flush your pots regularly like outside to prevent excess salt accumulation. If you do not have good lights, it is better not to fertilize in winter as that will help stunt their growth during this period.

You can pick whatever day length you want. Geographically, the longest days here exceed 15 hours and the shortest are just under 9 hours. Running 14 hours max and 10 hours minimum does not seem to have impacted seasonality for my plants.

If you look at seasonal variance in sun times of places like South Africa Little Karoo, the difference is less than what I see here locally. Another consideration is that in nature you get cloudy days and whatnot, whereas indoors you get 100% consistent light daily. This factors in to DLI (Daily Light Integral).

Essentially, you will always get more winter light indoors under lights than naturally, assuming you live in a place with a winter season with cloudy weather.

If you are growing in a space with natural light, I recommend keeping similar schedule to your local sun times, but you can extend it a few hours if you wish. If there is no natural light, just run your lights at night to save money if you have time-of-use electricity pricing.

Are you getting good compact growth in your apartment now under lights? If so, then keep it up and take advantage of winter than just surviving through it!

You can take some temperature measurements if you have a thermometer and post them here if you like. Honestly warmer temperatures are okay for the most part - you will just see better growth if it is cooler.

Not everybody is comfortable or willing to freeze for the sake of their plants, ha!

Thanks ewwmayo, for the detailed and thoughtful response!

I've been watering about every 4 days but temperatures are warmer. I have the lights synced in general with sunrise/sunset so getting about 9 hours each day (zone 7a).

Growth for my jades seems much more compact than prior winters. I definitely need to lower the lights more for some of my other succulents though to encourage even better results.

I'm curious as to what you use for the occasional spider mite? I think I saw somewhere mentioned having a good solution now. I've used either neem oil, mixture of rubbing alcohol and water 50/50, as well as permethrin, with varying results.

I've been keeping my cactus plants in a cold dark garage for 20+ yrs overwinter. Zero negative consequences. Just be careful in the spring acclimating to strong light. Garage stays between about 35 and 53F.

I decided to try this with my mesembs about 5 yrs ago. Previously I used T5 lights. Cold/ dark for a few months doesn't harm them either, just don't expect regular blooming from species like Argyroderma or Gibbaeum.

Aloes, echeveria, agave, many others are also fine with this routine.

Supplemental light does nothing for cactuses for me with the exception of Mammillaria plumosa and Turbinicarpus valdezianus which are budding up as I write. Those I give light. They are unusual in that regard.

So for those of you who are energy conscious, save the watts for something else or maybe just give your plants an early spring boost before exposing them to strong light in the spring.

x

Volcoff - Depends how many mites you have. Neem may work, don't think alcohol will do much really.

Good thread here: https://www.houzz.com/discussions/insecticide-pesticide-insights-dsvw-vd~3742440

X - I am not growing many cacti under lights, just some Astrophytum. Some growth but nothing special.

For my opportunistic Mesembs, Haworthia, and other succulents I am getting a lot more growth because I can extend the fall/spring seasons.

Many flower throughout the winter, which helps liven up my home. =)

Agree with you that it really comes down to cost. If a grower can afford the electricity, then they can take advantage of winter and keep growing.

Otherwise cool and dry will let them over winter until the spring. Zone 6a here we usually get good enough weather outside from late May to early November, so maybe just under 6 months outdoor growing season.

They are! Can tell you that I can't wait to move a large number of plants outside to the roof. =)

Kevin

Are your hardy pots under the poly roof??? If so - I think you baby them too much, haha. Mine are all buried under more than 2' of snow....will see if there are many casualties - I hope not, since I always did the same in the past :) Hardy means hardy to me, so they have to SOS (swim or sink, lol).

BTW, with your poly roof: if I had the same I would get some more 7.2mil and have sides hanging down too. And put the plants under earlier - it will be warmer there...JMO!!!

Rina - They are at the edge of my poly shelter. Half covered in snow right now. Had a hard time deciding to leave them fully exposed or shielded from snow and rain. Ended up going half half.

Hmm, I do have quite a bit of 7.2 mil left. Enclosing the sides for the shoulder season is an option.

Kevin

I have a half-finished small, unheated sunroom with a poly for the roof. It only gets morning sun - it is at the back of the house facing east, but trees & garage shade sunshine well before noon. It gets quite warm during sunny days even now, it was up to 16C recently. It would have to be vented. Once night temps stay around 4-5C, I am going to move plants there...but I do not have the finicky beauties as some of yours are - I would worry about those more :)

does anyone have suggestions for what kind of light bulbs i should get? I want a small bulb because i have just a few plants and i want it to fit in my lamp so I can keep it on my desk. are CFL 6500k the best choice.

There are some good options. First you need to check how many watts your lamp socket is rated for and second the lamp shade/reflector because that can limit what bulb you put in.

CFL or LED lightbulbs for desk lamp - either is good.

ewwmayo - you say you got the same intensity under lights as on your rooftop. OK, as an old retired physics teacher I don´t pretend to be familiar with the non-SI units that you are quoting, but the intensity of sunlight varies with latitude, being 100,000 to 200,000 lux, 1 lux being 1 lumen per metre squared. This is generally very much more than you can obtain from affordable and practical light sources. In one post you say your light source is 30,000 lumens, that will be radiated in all directions - if you could find an efficient reflector that would concentrate ALL that into a 1 meter square area you would have 30,000 lux - much less than sunlight. And in practical terms you probably lose a lot of light energy and don´t achieve near that. So I remain unconvinced.

PAR DLI is the best measurement and used by plant professionals worldwide. It is SI. Moles of light (mol) per square meter (m−2) per day (d−1).

Think of plants as light collectors over the course of the entire day.

Because there are no clouds, change in light angle, or trees casting shadows artificial lights can match the sun over the course of a day.

It is the consistency and reliability of artificial lights that makes up the difference of instantaneous intensity.

Define a mole of light. And day is not an SI unit, so anything per day isn´t either.

Sunlight is intense.. we're getting the first rays in a long time and when they hit the plants you can't even see the LED lights that I thought were bright. It's no wonder my house plants haven't grown much in winter.

Jeez. I think my brain just went apoplectic. We can slow photons down to my downhill speed on a bike. All that's left to do is make them stick together into molecules. But it could happen.

Can't do links on the phone so here..

https://m.phys.org/news/2018-02-newly-optical-state-enable-quantum.html

Sorry, I'm not here to argue. =)

It's been so busy over the past few months I've been barely able to be in this forum.

For me at least, fall/winter into the beginning of spring is the best time. It's an exciting time with lots of flowering action and highest amount of growth.

Right now there are 12 different species (plus 30 or so different Haworthia hybrids) budding and flowering under artificial lights for me.

So many weekends are busy and I'm not even able to see my flowing Mesembs open (specific times during the day), which makes me sad.

LOL !!!!!!! Love the Titanopsis !

After adopting ewwmayo's lighting setup last year, I have had amazing results. Tons of blooms, great compact growth and color. Couldn't ask for more... well maybe more space under the lights.

There's never enough space!

The trick is to get mesembs. They're so small you can get so many for so little space!

They grow so happily within the confines of their pots. And most of them stay pretty short, which makes growing so convenient.

I really appreciate all of you.

I know this is an older thread, but just wanted to post the light fixture I finally got. It's a Hydrofarm jump-start with stand. It's a 4ft full spectrum, 6400k T5 lamps at 54W, and 4 bulbs total. I cut down and painted a piece of old wood I have to raise my stapeliads and small euphorbias as close to the lights as I could. A lot of my stapeliads are tall (Rhytidocaulons) so this is as high as I could go without them actually touching the bulbs.

Planning on keeping it on during dark,overcast rainy days, which we've been getting too many of in upstate NY.

Anyways, thanks to Kevin and everyone on this thread for all the help in figuring out what might be best for these plants. Hopefully it helps them grow and flower. If anyone notices anything I'm doing wrong, feel free to let me know :)

Looking good and nice collection of interesting plants! Keep us posted on how they grow and things go! Just watch how things grow with the lights on and don't be afraid to shuffle your plants to optimize their location. =)

Thanks! One question I have for anyone who has set up grow lights: do you change your water schedule now that there is light on the plants full day? I've been watering everything once every 7-10 days (very small amounts of water for the Stapeliads) when they were in the windowsill without the lights.

One thing I've noticed, is that the plants I water fully until they leak at the bottom drainage holes seem to be growing more (my small euphorbia poissonii, my 2 small dorstenias, my cubiformis and my larryleachia).

I have been thinking about doing a full watering on the stapeliads instead of a couple teaspoons like I've been doing once a week, but I'm worried about rotting them. I'm debating whether two small waterings a week, or one full watering like I give the other small plants might help them grow and/or flower. They haven't done much growing if at all, unlike the others I mentioned above that get full water once a week.

If anyone has any thoughts, especially with them all being under lights now, that'd be great! They're all in pure grit mix too (all the above plants), so maybe a full watering on all of them will be a better idea.

Edit: Forgot to mention that with each water, I fertilize with Schultz Cactus+Succulent fertilizer. The greenhouse I got the cubiformis from said to do this on it since it's in pure pumice/rock mix so I did the same for everything in the mix.

Start slow and watch for burning - first week has the highest risks. You can increase watering a little if your plants are dehydrating faster. Eventually you may reach near outdoor growing watering levels.

Try to not change too much at once so it's easier to manage and see the effects. Nothing will die that quickly from being a bit dry, but too wet can be cause problems very quickly.