Spring Clone Planting Guide

[D.S. Toker. MD]

Over the past several years ive seen numerous threads asking about the time to plant clones in the spring and several threads asking why their clones were flowering. Ive worked through this problem and thought it might help if i shared what i have learned.

Lets consider a couple of things first:

The age and maturity of the clone has an influence on its response to changes in daylenth. The more mature the clone the faster it will respond to changes in daylength. A freshly rooted clone wont attept to flower as quick as a 6o day old clone.. Its my view that 3rd generation clones also are more responsive to daylength changes than either first or second generation clones. 3rd generation clones often finish a week or more sooner than 1st/2nd gen. clones.

Hybrid cannabis begins to flower at approx. 14.5 hrs of light. At my lattitude during the normal season, I begin to see my first pairs of flowers around August 1. Because cannabis takes approximately 2 weeks from the time daylength reaches 14. 25 hrs until the first sets of flowers are seen, then my plants are actually being triggered to flower around July 15. My daylength on July 15 is 14.5 hrs of daylight. (You can test this indoors by recording how long it takes from the time you turn the lights back to 12/12 before the first setss of flowers appear).


The key principle for insuring that your spring planted clones dont begin to flower is to avoid planting until your spring time daylength reaches 14.25-14.5 hrs of light. I have attached the Daylenght Explorer so that you can gauge when that point is reached at your lattitude:

My daylength at 38 reaches 14.25 or so on May 15. I usually fudge a little and plant around the 10th without problems, but if i transplant clones out on May 1, they will flower every time. If i transplant on May 7 they will begin to flower. . For several years ive planted around May 10th and i see quite a few flowers but the plants dont try and reveg. Although this year shows how close im cutting it because we had 25 straight days of clouds and rain and i saw a lot of female flowers.

Here are some proper transplanting times per lattitude; Dont fudge these dates by much more than a week

34N= June 15th
36N= June 3rd
38N= May 20th
42N = May 12th
44N = May 5th
48N =April 39th

http://astro.unl.edu/classaction/animations/coordsmotion/daylighthoursexplorer.html

 

[greenhaus]

even if you throw clones out in the times you suggest. they can still start flowering really small.

the trick is to put them under light for a week or so. and gradually drop the hours of daylight down till your around 16hrs.

or else they flower no matter what

 

[Stress_test]

If I know the clones will be going outside, I start em at 16/8 as soon as they are rooted anyway. They almost always start flowering when placed outside after a few days.

I have been contemplating reducing their light to 14 or 14.5 hours/day though. I may just start doing that from now on and see what happens.

 

[mapinguari]

There's some useful discussion of early flowering and supplemental lighting in the Growing large plants outdoors thread, like here for example.

I have been using a 50' string of contractor lights with 13w fluoros in them as supplemental, some dudes use even more, methinks. Dudes like Butte and nomaad and Trinity Gold and Ganja D are the ones I learned about this from, some of them even make their own strings of lights, lots cheaper if you have the electrical chops.

 

[.clunk]

Root restriction leads to flowering in alot of clone only strains, so I try and make sure nothing get's too rootbound. I'd rather plant early, than plant rootbound clones since it seems they'll reveg if the light cycle isn't perfect, but if they're rootbound they might continue to flower.

I have read that triachontinal (spelling?) inhibits flowering and will force a plant back into veg. Superthrive contains the hormone, so does alfalfa meal (and it costs alot less). I've had some mother plants that were starting to flower because they were rootbound, I gave them a heavy top dressing of alfalfa meal and they snapped back into veg pretty quickly, and have been chugging along in full veg-mode even though I put them outside a few weeks earlier than I normally would.

I try and give them a high dose of nitrogen after the roots are established and they've been transplanted outside, in an aid to discourage early flowering.

I try and cut the lights back gradually, an hour per week or so before I plant them. This year I took it down to 17/7, no preflowers on the plants outside yet.

In a perfect world, I'd be able to have supplemental lighting in the bush, but since I'm not working in my backyard it's a bit of a laughable idea for me.

 

[zwh]

How can you tell if a flowering plant is going to revert back? I put some clones outside pretty early this year expecting them to eventually revert back, they're all flowering and all seem to be stuck in flowering (they look about 2 weeks), except one seems to be continuing on flowering even though the day length keeps increasing.

It's now June and I'm losing hope on these. Are they ever gonna revert back?

 

[greenhaus]

the trick with switching down the hours of daylight is to do it slowly.
a half hour reduction every day or two is best.
until you are around 14.5-15.5 hours is best. so when you place the plant outside it
wont trigger flowering.

 

[Manstien]

Great thread DS, always interesting to hear information on this topic since the last thread wasn't fully concluded even though people like Butte did drop in solutions, some peopel do not have the option to use lighting outside....

What if you do start to get flowers isn't it possible to remove the pre-flowers and give a heavy dose of N? to avoid any trouble root bound is bad also not matching daytime hours +/- 30min for sun?? very interesting topic...

 

[D.S. Toker. MD]

How can you tell if a flowering plant is going to revert back? I put some clones outside pretty early this year expecting them to eventually revert back, they're all flowering and all seem to be stuck in flowering (they look about 2 weeks), except one seems to be continuing on flowering even though the day length keeps increasing.

It's now June and I'm losing hope on these. Are they ever gonna revert back?

You'll start seeing the little buds thin out and leaves will start growing where the buds were. Flowering changes generally take 2 weeks ZWH. If your clones are in full flower, then about 2 weeks after your daylenth exceeds 14.5 hrs of light. Everything is tied to photoperiod and daylength.

 

[D.S. Toker. MD]

Great thread DS, always interesting to hear information on this topic since the last thread wasn't fully concluded even though people like Butte did drop in solutions, some peopel do not have the option to use lighting outside....

What if you do start to get flowers isn't it possible to remove the pre-flowers and give a heavy dose of N? to avoid any trouble root bound is bad also not matching daytime hours +/- 30min for sun?? very interesting topic...

I havent read the big plants thread simply because im a guerilla grower and most of those grows are legal. There's not much in common between the 2 types of growing. Im not sure why one would use outside lighting with clones, but then as i said, im not a legal grower and cant even consider such issues.

I often get a few flowers but i pay them no mind. As long as daylengt is getting close to 14.25-.5, flowering wont continue. People often use too much lighting to grow their clones and that creates big photoperiod problems for them in the future. Its my view that a clone intended for outdoors should never recieve more than 16hrs of light, and that should be reduced to 14.5 for a week or so before transplanting. Back when i was trying different methods, any approach that i attempted that involved more lighting than 16 hrs, ive had problems getting the plants acclimated to 14.5 hrs without flowering.

 

[StrapAssassin42]

I dont plan on putting my girls out until just before the summer solstice...
If im running 24 hrs of light in my veg room now am i to anticipate problems with 15 hrs of light (or a little under), outside?
The whole thing seems a little counter intuitive to me... i understand why the plant wants to flower initially but the days are getting longer!
I would think the plant would realize this very quickly and correct itself.

 

[zwh]

You'll start seeing the little buds thin out and leaves will start growing where the buds were. Flowering changes generally take 2 weeks ZWH. If your clones are in full flower, then about 2 weeks after your daylenth exceeds 14.5 hrs of light. Everything is tied to photoperiod and daylength.

Thanks, Toker. I'm at about 14.5 right now, so hopefully by the end of June they'll be back in full veg. Will it help to pick the flowers off? The one clone of mine that is in full flower is full of trichs, smells really nice, might even be hashable.