Pure sativa's don't like CFL?

[MostlyMe]

I have a little veg cabinet with CFL bulbs that I have used successfully many times for pre-growing. It is not as fast as using MH lighting, but good enough to get a head start while another batch is finishing up flowering. My Zamaldelica (F) and CBG Destroyer (F) (from seed) didn't seem to like it though: growth was slow and after two weeks yellowing started from the cotyledon up towards the new growth. I've seen the cotyledons and first set of leaves shriveling up early before, but when I noticed slight yellowing of the first set of three-fingered leaves today, I repotted and put the ladies outside even though I would have preferred to do that when the weather is a little better.

I have no experience with pure sativa's, and I treated them just as I treat all my girls. The only thing I can think of is that these pure sativa's don't like CFL light. Did anybody else notice this?

Just to describe the environment:
- 3 CFL bulbs for 2 plants (23 W, 4000 K)
- 0,7 l pots with seedling soil
- Temp 22 C in the root zone
- Kept fairly dry (roots looked healthy and well developed when repotting)

 

[The Hatter]

Sativas do prefer intense light sources but usually the signs of insufficient light are stretch and poor vigor rather than the symptoms you are describing. How close were they to the lights?

The yellowing sounds more like a nutrient or ph problem. I've noticed that Sativas tend to be much more finicky about nutes than indicas. You can literally dump double the recommended dose of a cheap poorly balanced chemical fertilizer like miracle grow on an indica and it will usually grow fine where as the same exact treatment will outright kill a sensitive sativa.

I haven't popped my zamaldelica seeds yet but I do have experience with Destroyer and it was the most sensitive strain I have grown as far as ph and nutes go. It suffered symptoms very similiar to what you are describing. Do you have very high ph hard tap water where you live?

 

[RandyCalifornia]

Sativas grow better then nothing under CFL's especially seedlings. Like the Hatter said MostlyMe it sounds like something else. Maybe overwatering. Pics would sure help.

 

[DemonPigeon]

I've never had a problem with CFLs and pure Sativas

 

[Terpene]

Sativas don't like CFLs, they LOVE them. This is a pure haze (tom hill's haze) under nothing but CFLs 16 weeks into 11/13.

Your issue sounds more like nitrogen deficiency from being rootbound and using up the minimal nutrients in your mellow seedling soil. Pure sativas need a ton of room for their roots or they start looking really unhappy. I pop beans in fox farm happy frog straight out of the bag under cfls and every seedling I have looks like my Purple Haze x Malawi:

That's about a 1liter container, when they start looking like plants, I pot up to a 1gallon, then a 4gallon, then a 10gallon. Side note - fox farm's ocean forest looks killer on the label, but its way too hot for just about everything I've ever put in it. Happy frog ftw.

 

[MostlyMe]

Thanks all, great input!

Sativas do prefer intense light sources but usually the signs of insufficient light are stretch and poor vigor rather than the symptoms you are describing. How close were they to the lights?

The yellowing sounds more like a nutrient or ph problem. I've noticed that Sativas tend to be much more finicky about nutes than indicas. You can literally dump double the recommended dose of a cheap poorly balanced chemical fertilizer like miracle grow on an indica and it will usually grow fine where as the same exact treatment will outright kill a sensitive sativa.

I haven't popped my zamaldelica seeds yet but I do have experience with Destroyer and it was the most sensitive strain I have grown as far as ph and nutes go. It suffered symptoms very similiar to what you are describing. Do you have very high ph hard tap water where you live?

They were a few cm from the lights, as CFL doesn't get hot at all. I grow organically and with RO water, so pH is not an issue for me. No nutes used yet anyway.

Sativas grow better then nothing under CFL's especially seedlings. Like the Hatter said MostlyMe it sounds like something else. Maybe overwatering. Pics would sure help.

Definitely not overwatering. I will see if I can get a few pics on here later.

I've never had a problem with CFLs and pure Sativas

Noted!

Sativas don't like CFLs, they LOVE them. This is a pure haze (tom hill's haze) under nothing but CFLs 16 weeks into 11/13.
View Image

Your issue sounds more like nitrogen deficiency from being rootbound and using up the minimal nutrients in your mellow seedling soil. Pure sativas need a ton of room for their roots or they start looking really unhappy. I pop beans in fox farm happy frog straight out of the bag under cfls and every seedling I have looks like my Purple Haze x Malawi:
View Image

That's about a 1liter container, when they start looking like plants, I pot up to a 1gallon, then a 4gallon, then a 10gallon. Side note - fox farm's ocean forest looks killer on the label, but its way too hot for just about everything I've ever put in it. Happy frog ftw.

Well, that's as convincing as it gets CFL is fine! Your diagnosis is probably right on the money too. Usually my plants grow much bigger before they start asking for a repot, but apparently sativa roots get claustrophobic much more easily

They are in 11 l Gold Label Custom (soil/coco) now and made it through the fairly cold night (8-10 C) just fine.

 

[MostlyMe]

Here's a picture, as promised. No signs of N-def getting worse, but they do seem to bit a bit cold (purple stems and even pinkish base of some leaves). It's gonna be hard keeping them alive here at 52 N until September, when I will transfer them back indoor to finish. Unless the summer takes off of course

 

[dubi]

Thank you all for your help and great tips

MostlyMe, you just need to increase light intensity, sativas indeed love CFLs for vegging. Best wishes!

 

[MostlyMe]

I think I'll use my trusted MH for vegging next time. That also allows me to start in bigger containers.

 

[Pinnate]

IMO, your plants appear to be suffering the effects of poor drainage ─ if they were mine I'd repot in compost containing enough sand to allow free draining . . .

 

[satva]

Just to describe the environment:
- 3 CFL bulbs for 2 plants (23 W, 4000 K)

Fluorescent - CFL or T5 lights:

Seedling and vegetative growth 5000k Full specturm - 6500k Daylight CFL for seedlings and vegetative growth.

Flowering - 2700k warm white

I read somewhere that the 3500k - 4000k range in flourscents was not effective for plant growth.

Normal sunlight is 5600k and is lower in the morning and evening cloer to the 2700k range. i believe the 2700k range is the best for flowering.

I grow sativa hybrids with a mix of T5 flourescents and Colorado sun which is very intense this time of year. I contain the size with small pots, which allows me to move the plants from inside to outside. I increase the pots size about 3 weeks into flowering.

Colorado light cycle is about 14 /10 now and will be 12/12 about September 14 - 21. Our first hard frost is usually October 1 - 14. In Colorado 12 - 14 week flowering sativa / sativa hybrids need to be finished inside in Colorado. A small greenhouse or big cold frame is helpful in extending Colorado's growing season. It is very sunny and dry even in the winter.

 

[burmese]

if you have low light conditions try some real seed company nepalese sativas. they grow like crazy and of unusual quality. I have grown myself nanda devi with 23w cfl 1month was 80cm 20-25cm leafs with 5-6 sets of leafs. Second i have grown pahari/kumaoni/farmhause in winter with the same cfl lamp and it gets 40 days to grow 60 cm with 15cm leafs /5sets of leafs/,, was smaller than nanda because it gets max.10Celsius in day and up to -10Celsius night. I grew her on balcony //2mm fat wood box// with constant 24 hour 23w cfl light that add some small heat. YES nepalese sativas can do that for low light and frost. ++my nanda has resin on first leaves and can grow easily with 1 litre earth into 2meters monsters. Kumaoni//pahari// was destroyed because of smoke her leaves with extremely clear and euphoric sunny high.

 

[burmese]

I forgot add info that it was warm cfl //2700K// and not cool white cfl, so if you calculate this, than nepalese sativas are really survival strains if they grow so easily in vegetative stage with poor 23w flowering stage lighting.

 

[MostlyMe]

From what I can tell, the jury is not out on the 4000 K. Some people don't seem to have a problem with it, others say it's a no no. Maybe I'll give it another try mixed with a 2700 K I have lying around. Or maybe not, since I like starting my babies in their final (air)pots now, which don't fit in my CFL grow box. I just make a little hole in the soil, fill it with seedling soil and plant in that. Beats repotting IMO.

Anyway, my sativa's did well in the outdoors, despite my torture. I tied them up to keep them bushy, deprived them of nutes and exposed them to unseasonably cold nights. They are now both in flower, after two weeks of artificial long nights. Here they are 10 days or so ago:

Zamaldelica

Destroyer

 

[satva]

MostlyMe - lovely structure and branching on the Zamaldecia and Destroyer those should flower nicely with a fairly even canopy.

"despite my torture. I tied them up to keep them bushy, deprived them of nutes and exposed them to unseasonably cold nights". <lol> sounds like my growing style. I did all that, and more to get a Highland Mexican (Guerrera) x blueberry to slow down and branch, she'd have none of that. I finally figured out she was a male. <vbg> Luckily he has a sister. I'm not sure how much you the quality of the high by smoking male leaf. but if so then I favor the high from that HM x BB male over the mango haze (mango pheno).

terpene - those Tom Hill haze at 16 weeks are inspirational, like it or not - you're my new CFL hero! The most haze influenced I've grown micro -tortue - style with T5 / CFL is Mango Haze. There was a hazy pheno ready in 14 weeks (more hazey than the mango pheno) that I liked. I tried to reveg after a 14 week harvest and it just died on the plant turning a beautiful gold / orange color.

My interest is in Ace or Cannabiogen's strains, (the ones I knew from the mid- 1970's), breed with say Mango Haze. Highland Mexican, Highland Colombian Gold and Nepalese hash were favorites, but homegrown was the best.

 

[dubi]

Beautiful sativa bushes MostlyMe

Looks like the initial problems were solved, your plants really inspire beauty and health, there's no doubt they are enjoying your good cares and your garden conditions, go on!

 

[Terpene]

Seedling and vegetative growth 5000k - 6500k
Flowering - 2700k warm white

I read somewhere that the 3500k - 4000k range in florescent was not effective for plant growth.

In my experience, color temp of the CFLs will definitely affect growth. However, I have yet to run into a color temp of CFL that doesn't work for growing.

Yellow/Red (2700-3000k) lights will encourage pretty vigorous branching "limey" plants, but at the expense of a lot of stretch. Running only 2700k lights will increase your inter-nodal distances a bit. In flower, bud size goes up, but frost goes down the redder the light gets.

Blue (5000-6500k) lights will make em squatter, "bluer" and in my experience veg a little slower. In flower, they tend to produce more frost at the expense of bud size. Would tend to make sense as higher elevations see bluer light and frost is the plant's defense mechanism.

White (3500k) lights split the middle of the two, leaning more toward lime green / stretchy / bud size. For ease of buying, I only run 3500k lights in veg and flower when using CFLs.

My best results with CFLs are with a mixed spectrum of bulbs. I try to spread all three color temperatures (2700k / 3500k / 5000k) over an area, rotating the plants to give them an even light temperature experience.

I've never tried timing the light color to correspond with plant age. By that I mean vegging under 5000k bulbs (spring) then running 2700-3000k (mid summer-early fall) through bud development and then switch to 5000-6500k bulbs (late fall) as they finish and swell to encourage more frost. That type of lighting switch would also tend to mimic the red-blue shift in natural sunlight through the seasons as well. Would make an interesting side by side experiment, that's for sure.