Distance of the artificial light.

[JCcares]

Soon cooler temperatures will force all my Cacti back into the basement for winter. See images.

Is there a preferred average perfect distance that the light should be measured from the top of the cacti?

Thank you for sharing your experience.

Last year most of these did not hibernate many produce some very nice flowers the temperature averaged around 60°.

Thank you

IMG_2830.jpeg (236.24 KiB) Viewed 2681 times

[ohugal]

Well to start off, the columnar cacti will receive more light than the globular. If you know the brand of your growing light, it's worth looking up whether there is a chart available with the intensity of the lamp in relation to distance. If there is no such chart available, a light meter would be very practical. I have myself have a PAR meter which measures photosynthetically active radation, but such meters in general are costly. You have to know light decreases significantly when you move away (sideways) from the lightsource (lamp), especially with LED's. Looking at your photo's you seem to have a full spectrum lamp, which is good. It saves you some additional calculations. If your growlight has a chart and it is expressed micromol/m²s (measurement of PAR), the minimum requirement for cacti is 500 micromol/m²s for about 8-12 hours a day. Off course lower temperatures are equally important to keep the cacti dormant.

Perhaps also check out Download's post, he seems to know it a bit better than me: https://cactiguide.com/forum/viewtopic. ... fd#p386068.

[greenknight]

Yep, it depends on the light output.

There are light meter apps for smart phones, some aren't too bad.

[JCcares]

Well to start off, the columnar cacti will receive more light than the globular. If you know the brand of your growing light, it's worth looking up whether there is a chart available with the intensity of the lamp in relation to distance. If there is no such chart available, a light meter would be very practical. I have myself have a PAR meter which measures photosynthetically active radation, but such meters in general are costly. You have to know light decreases significantly when you move away (sideways) from the lightsource (lamp), especially with LED's. Looking at your photo's you seem to have a full spectrum lamp, which is good. It saves you some additional calculations. If your growlight has a chart and it is expressed micromol/m²s (measurement of PAR), the minimum requirement for cacti is 500 micromol/m²s for about 8-12 hours a day. Off course lower temperatures are equally important to keep the cacti dormant.

Perhaps also check out Download's post, he seems to know it a bit better than me: https://cactiguide.com/forum/viewtopic. ... fd#p386068.

Wow!!!! THANK YOU Ohugal. Oh Man am I in trouble. I feel like a bad father. I have so many cacti and not sure which are Globular or what.

I have 2 “ Mars Hydro 2023 New TSL2000 300 Watt Led Grow Lights”. I was hoping to set both lights wide open and one light higher for the more mature cacti I have and the other light lower over the shorter smaller younger cacti.

Is there some rule of thumb distance safe to get my babies through the winter healthy happy?

Thank you

[JCcares]

Soon cooler temperatures will force all my Cacti back into the basement for winter. See images.

Is there a preferred average perfect distance that the light should be measured from the top of the cacti?

Thank you for sharing your experience.

Last year most of these did not hibernate many produce some very nice flowers the temperature averaged around 60°.

Thank you IMG_2830.jpeg

[ohugal]

Ok. Here's a link to the product page of your lamp: https://www.mars-hydro.com/tsl-2000-led-grow-light. At the top of the page you can scroll through some images, one of them is a PPFD chart. Just to be sure, your Mars Hydro has a dimmer right? So if you want to reach a PAR of 500 micromol/m²s, which is the minimum requirement for cacti, your lamps should be at a distance of 30cm from (the top) of your plants. Your dimmer should be set at approx. 36%. It can also be 40%. I'm quite new to this myself, so I'm just using the data and information I gathered from the internet over the past months. If you look at the chart you see the light intensity decreases at the edges. At a distance of 30cm, the light covers a surface area of 2x4 feet. The light is the strongest in the center 1x3 feet. At the edges at 40% intensity it varies between 194 and 365 micromol/m²s. I don't have the experience to tell you what the effect is of plants positioned at the edges. I also don't know what the best solution is for columnar cacti. I would position them just outside of the center 1x3 feet area.

[jerrytheplater]

I bought a similar style 150 watt LED last fall. I placed my Madagascar Euphorbia at the outside of the light area since I grow them with morning light up to about 1 pm in the summer. They are right up against my house which faces exactly east. The plants and seedlings that want the most light are in the center.

This is what I bought. https://www.amazon.com/VIPARSPECTRA-Com ... _ec_t&th=1 I grow my warmth needing cacti/succulents under it. I made a copper tubing suspension system that fits on a 4'x4' piece of plywood. It is 5' tall and lets me lower the light to just above the plants. It is dimmable. I don't monitor the light intensity with a meter. The plants did well last winter. I intend to do the same this year.

[JCcares]

Ok. Here's a link to the product page of your lamp: https://www.mars-hydro.com/tsl-2000-led-grow-light. At the top of the page you can scroll through some images, one of them is a PPFD chart. Just to be sure, your Mars Hydro has a dimmer right? So if you want to reach a PAR of 500 micromol/m²s, which is the minimum requirement for cacti, your lamps should be at a distance of 30cm from (the top) of your plants. Your dimmer should be set at approx. 36%. It can also be 40%. I'm quite new to this myself, so I'm just using the data and information I gathered from the internet over the past months. If you look at the chart you see the light intensity decreases at the edges. At a distance of 30cm, the light covers a surface area of 2x4 feet. The light is the strongest in the center 1x3 feet. At the edges at 40% intensity it varies between 194 and 365 micromol/m²s. I don't have the experience to tell you what the effect is of plants positioned at the edges. I also don't know what the best solution is for columnar cacti. I would position them just outside of the center 1x3 feet area.

Thank you VERY much Ohugal to help me understand all this

[JCcares]

I bought a similar style 150 watt LED last fall. I placed my Madagascar Euphorbia at the outside of the light area since I grow them with morning light up to about 1 pm in the summer. They are right up against my house which faces exactly east. The plants and seedlings that want the most light are in the center.

This is what I bought. https://www.amazon.com/VIPARSPECTRA-Com ... _ec_t&th=1 I grow my warmth needing cacti/succulents under it. I made a copper tubing suspension system that fits on a 4'x4' piece of plywood. It is 5' tall and lets me lower the light to just above the plants. It is dimmable. I don't monitor the light intensity with a meter. The plants did well last winter. I intend to do the same this year.

Thank you Jerry I get what you say. Appreciate you taking the time to help me again. Our Creator He did one amazing beautiful job on this privilege planet.