Eastern US Indoor Grow Question

Ok, first a few assumptions so that I may pose this question clearly.
1. Location is Eastern US, 38-40 latitude. Goal is to grow in greenhouse environment under natural light in early spring, Mar-May.
2. Mother plant is (to be) healthy and of a 45-day "trigger happy" sat-ind cross.
3. Mother is (to be) growing indoors under a 18-hour per day HID light regimen and is in a fully vegetative state at the time cuts are taken.
4. Cuts are (to be) taken on February 1, 2010. Cuts are rooted under flourescents then moved to a HID for modest grow-out.
5. At this point it is Mar 10, 2010, 5-6 six weeks later, and it's time to bring them out into the greenhouse (natural light) for blooming.
6. Sun is on the ascendancy and days are barely 10-12 hour total daylight, still quite short. It is 90 days until the solstice where there will be 16 hours of daylight.
Ok, here's the question as best as I can phrase it:
Without using supplemental lighting in the greenhouse to "extend" the day-length, can the young plants be counted on to go into and STAY INTO bloom, given the short days and the gradually increasing day-length of late Mar and onward into late May and June.
This question gets to the heart of whether cannabis is more sensitive to day-length (like mums, pointsettias) or crop-time length (like corn). My understanding is limited. I think most of us assume it's day-length that triggers cannabis; hence the general method of moving from 18-24-hours down to 12-hours at bloom time. But can a plant that was fully vegetative under a STRONG 18-hour cycle as a young vegetative cutting be counted on to GO BLOOM and STAY THERE in the early spring under NATURAL LIGHT ONLY as the day-length gradually increases to it's max on June 22nd?
The reason for getting this question answered clearly and accurately in advance is obvious; if this growing can't be done without supplemental lighting and the necessary electricity and photo-period manipulation curtains (standard in the green house industry) then plans for these things must be made well in advance or greenhouse growing scrapped altogether.

Any EXPERIENCED advice and input would be GREATLY appreciated.
Peace.

Hey man, I grew in the North east for years. Although I do mostly indoor, every year I would try a few out-side and/or in the green house. I tried putting out some out early also. The answer is no it can't. Marijuana is extremely light sensitive. Chemical changes happen inside the plant as daylight is decreased. I won't get into details but a few threads here can give you all the info your looking for. When I tried to flower early in the season as daylight hours grew longer the plants reverted back to veg. - even when I would pre-flower indoors. The only solution was to use natural light for 12 hours a day and then black her out for the other 12. My plants that reverted back to a vegitatative state spent so much time doing retarded things through-out the summer that the harvest was seriously diminished.

Ok, so plan to use supp light and shade curtains then?

kidsnmotion said:

Ok, so plan to use supp light and shade curtains then?

Click to expand...

IMO/E.. it is going to be some what strain, pheno' dependant. "Most" will remain in flower, as long as your hours do not exceed 14 hours of light "IME". BUT.. providing 'less' than 12 hours of light will also effect potency and yeild. Studies have revealed that nearlly twice as much thc is produced under 12 hours of light, than under 10 hours.
I used a heated GH situation for the entire winter a few years ago, and flowered under the natural cycle of winter light. "I" was disapointed in the results. I'm "around" the 38th too.