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View Full Version : What are light cycles and how do I use them?



lkdj2003
05-06-07, 12:57 PM
The amount of time your garden should be exposed to lighting depends on what 'cycle' your garden is in:

The 'Vegetative Cycle' of your garden starts with the sprout of the seedlings and can be continued indefinitely. In the veg cycle your garden will require a minimum of 16-18 hours of light and 6-8 hours of darkness daily. Since a given amount of light can only do so much, equal production can be realized in a smaller space with less plants, where the light is concentrated and the plants can grow more efficiently. Using more light helps additional co2 uptake.

Since a plant can be kept in the 'Veg cycle' indefinately, many growers cultivate 'Mother' plants. This plant is used for clone starts and never produces buds, only new growth.


The 'Flower Cycle' or 'Bud cycle' is typically equal amounts of light and dark, 12 hours on, 12 hours off or 12/12. This produces a change in the plants metabolism simulating Fall, shorter days....less light.

This is the cycle that the plants will show their sex. Usually, you'll be able to determine the sex within the first 2 weeks of 12/12. By the 3rd week most plants have developed healthy bud sites or pollen sacks.
The plants will continue on the 12/12 cycle until harvest.

When someone 'Re-vegges' a plant that has been in the flower cycle, they're switching the light cycle back to 18/6 to stimulate new vegetative growth.

smokingnoob
15-12-08, 03:26 AM
very helpful

sid
06-08-09, 11:08 PM
Good post I needed this info

Vetran
17-09-09, 03:14 PM
THought i would ask this question here... How would a auto flower plant react to 24/7 of light... I have a few mums under 24/7 of light and i think one of my young mums may be a auto im not sure its just the way she is looking over the last 2 weeks... would she still flower on 24/7 of light... cheerrrrs

dj #
17-09-09, 03:20 PM
yes she will still flower, but 20/4 or 18/6 would give her roots a chance to grow too ;)

Vetran
17-09-09, 03:22 PM
Nice1 dj... Ive allways left my veg plantson 24/0 just didnt know if a auto would react in a bad way to 24/0 ;)

thanks again

massivemick
24-11-09, 10:19 AM
can someone please just give me a roundabout weekage .......from germination ive had my seedlings on 16/8 for a week.....how long should i carry this cycle on for??????? really i want to know from this point how many weeks veg and how many weeks flower.....my northern soul strain says its 12 weeks to harvest so will i do 6 weeks on 18/6 and 6 weeks on 12/12

Seeker2be
17-01-10, 04:24 AM
I am a novice grower yet to start. I have done research on multiple sites and posts but I have not seen this addressed: If 6500K is for vegit growth and 3000K for budding or flowering what happens if you just go with 6400K for 24/ 7 for 8-10 weeks then shift to 12/12? When you shift to 12/12 should you then add 3000 K lights to the side? If 12/12 promotes flowering then how and when should the 3000K be used?

Second question:Closet grow: Sunblaze (20,000 lumens) with 4 T5 bulbs 54 watt each 6500 from above or one or 2- 200 watt CFL (12,800 lumens each) with reflector from above? Would right and left side T5 singles 54 watt or cool white and warm white mixes on either side be best? and when to place/use them? During the 24/7 or 12/12. Goal 6 plants . sorry for the convoluted question. Seeker

Seeker2be
17-01-10, 11:18 PM
2300-2700 K not 3000. Sorry still learning. Seeker