顯示具有 photoperiod 標籤的文章。 顯示所有文章
顯示具有 photoperiod 標籤的文章。 顯示所有文章

2008年5月14日 星期三

Grow in the dark?

Do Roots REALLY grow in the dark?
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Many times I’ve seen in posts that “roots grow during the dark.”. If this were true, the 24/0 photoperiod would result in a plant with a tiny root structure, if one at all!

We know this is not the case - so how does it actually work? To simplify things, lets use an analogy. Try to think of a plant as a building… one constantly under construction. The plant needs raw materials, (fertilizers and water), and energy (light) in order to “build itself”. The raw materials are the “bricks and mortar” of the building. The energy is the workers, vehicles and power tools used to assemble the building. The Plant is capable of storing some raw materials and some energy for use later, but the amount is limited...think of a warehouse and a battery.

During the day, (Lights ON) the plant is collecting and storing light energy, and is using and storing raw materials. The plant is stockpiling raw material, and is charging it’s batteries… it is ALSO using raw materials and using the energy it is collecting. It’s building itself, literally putting itself together. During the day however, the plant is not as efficient at building itself, as it is at night (lights OFF.) It can build itself, but not as quickly. While the lights are OFF, the plant is using energy and raw materials to build itself…. the plant is more efficiently using the raw materials that it stored during the day. The plant is better at transporting and assembling the raw materials.

The bad news: since there is no light energy, the plant must rely on energy it stored while the lights were ON (its stored energy). (Essentially, the plant is running on batteries, and using raw material from the warehouse.) There is no light energy to collect. Since the plant needs energy to absorb more raw materials, it is easier for the plant to use raw materials that it stored during the day than it is to absorb raw materials through its roots. Although the plant IS capable of “doing it all” with the lights on, (Collect, store and use energy & raw materials) it does a better job of actually doing the work (using the energy and raw material) while the lights are out.

During the dark however, it relies solely on its limited supply of stored energy and stored raw material. One last thing to remember is the fact that a plant will always strive to maintain a balance between the size of its roots and the size of its canopy (Leaf mass.) The roots must be big enough to supply as much raw materials as the canopy can use, and the canopy must be big enough to provide the energy required to store those raw materials… Trim the roots on a healthy plant, and canopy growth will slow to a crawl until the roots have grown big enough to again support the canopy. Trim the TOP of a healthy plant, and root growth will slow similarly, until the canopy has grown big enough to again support the roots.

If the plant is already in balance, the canopy and the roots will grow at the same rate. If you actually measured them several times daily over several days, you’d notice that they actually DO get bigger at night, but roots and canopy at the same rate, unless either has been trimmed, and as long as the “batteries” hold out.

Manipulate photoperiod

How do I manipulate the photoperiod for larger yields?

[DISCLAIMER]: This information is provided as experimental data and not fact.
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The only photoperiod manipulation from years of experiments that offered discernible improvements was the following photoperiod adjustment made for 1 or 2 calendar weeks at the point of maximum flowering rate: Daylength of 21 hours, 36 minutes with a dark period of 12 hours. To accomplish this, you need a 7 day, 24 hour digital timer. During a 7 day calendar week on Earth, the "sun" only cycles 5 times. This permits easily switching back to the regular 12/12 at your discretion. You may want to only alter during peak flower production to stimulate the plant's metabolism. Using this photoperiod throughout the flowering cycle will cause this:

A variety that takes 49 days of 12/12 to mature, won't see 49 - 12 hour dark periods under 21:36/12 until almost 10 calendar weeks have passed.
The total increase in light energy is almost 80%, which will produce larger yields, if all of your other enviromental conditions are kept optimal.
The total increase in flowering period is only 40%, half the potential room for improvement. This means you don't have to be perfect to win out.

Selective application of the 21:36/12 photperiod for only 1 or 2 weeks extends the wait only 2 to 4 Earth days, which makes up the missing 2 complete day and night cycles each week on Planet Ito. This permits the additional light energy to be provided without purchasing additional equipment or overloading existing circuits, which maximizes the existing system's capabilities. The main advantage is that matched with co2 and optimal nutrition, the plants metabolism will increase dramatically. I have only successfully tested this photoperiod for two weeks. The potential for a net increase of 40% over the entire cycle (80% increase in light energy vs. 40% longer wait) is worthwhile. Don't be afraid!

Day 1 - Sunday, 6:00am til Monday, 3:36am Day 2 - Monday, 3:36pm til Tuesday, 1:12pm Day 3 - Wednesday, 1:12am til Wednesday, 10:48pm Day 4 - Thursday, 10:48am til Friday 8:24am Day 5 - Friday, 8:24pm til Saturday 6:00pm