Of the three glandular trichomes produced by drug-type marijuana, only the capitate-stalked glandular trichome in the presence of the UVB photon has the phytochemical capacity to produce the amount of THC associated with euphoria and hallucinations.

The capitate-stalked glandular trichome is triggered into growth on the floral bract and concomitant leaves either by fertilized ovum or by photoperiodically-induced parthenocarpia.

A female plant grown from a seed that was the result of an ovum fertilized by pollen from a male plant (Sativa or Indica or Thai or Mex or whatever) will only exhibit parthenocarpia if the photoperiod is less than 12:00 hours (post-equinox).

On the other hand, an Indica female plant grown from a seed that was the result of an ovum fertilized by pollen from the female parent, or from another Indica female, (self-pollinated or cross-pollinated) may exhibit parthenocarpia when the photoperiod is longer than 12:00 hours (pre-equinox). Seeds of this type, which the writer labels "homozygous" to differentiate them from the seeds produced by male pollen--which the writer labels "heterozygous"--were found by the writer in the mid-1970's in an Indica marijuana from a commercial grow in Northern California. The growers of this Indica marijuana, following the guide of the folks in Northern India, are careful to kill all the male plants as soon as they show their sex so that any seeds that do show up will be from an ovum fertilized by female pollen; these seeds will provide another generation of female plants that may also exhibit long-day parthenocarpy during flowering.

The whole purpose of breeding for long-day parthenocarpia obviously is to have the capitate-stalked glandular trichome's exuded resin sphere (a UVB receptor) present when the levels of UVB in the pre-equinox sunshine in the Northern Hemisphere above the Tropic of Cancer are at least high enough to cause sunburn. The fact that the folks in Northern India put this genetic story together thousands of years ago is quite interesting in view of the fact that so many caucasoids trying to grow seedless marijuana today have not picked up on it. That's very telling.

The marijuana seeds available to the readers are most likely "heterozygous" because male pollen fertilized the ovum, and a 12:00 photoperiod will not trigger parthenocarpia in any female plants grown from these seeds. This means that only the resin spheres from the bulbous and capitate-sessile glandular trichome will be in a harvest from a seedless "heterozygous" marijuana grown with a 12:00 hour photoperiod. However, an 11:00 hour photoperiod will trigger parthenocarpia in seedless "heterozygous" marijuana, and this will also trigger the growth of the capitate-stalked glandular trichome. The capitate-stalked glandular trichome will produce more THC, even with only the UVA photon in the light stream, than will the bulbous and capitate-sessile glandular trichome together in the pre-parthenocarpic 12:00 hour photoperiod.

Using artificial light and/or shaded greenhouse to manipulate the photoperiod, the indoor grower will start with an 11:30 hour photoperiod instead of a 12:00 hour photoperiod. This will hasten marijuana's move from vegetative growth to flowering and may even trigger parthenocarpia in some "heterozygous" gene pools. But it is when the photoperiod is reduced to 11:00 hours that parthenocarpia will be complete in most all "heterozygous" marijuana except for an extremely short-day flowering type which may need a 10:30 hour photoperiod for parthenocarpia to be complete.

Because the photoperiodic niche that triggers parthenocarpia and the growth of the capitate-stalked glandular trichome is a genetic thing, the readers are advised to experiment with photoperiod duration to find the one that works best in bringing forth parthenocarpia in the marijuana they are cultivating. In any case, the readers are advised to break the 12:00 hour photoperiod habit and go for the shorter flowering photoperiod to see what they may have been missing!

As was pointed out in the section about the photoperiod, the light in the first and last hour of the outdoor daylength is composed mostly of long wavelengths (such as orange and red) because of the scattering effect on the shorter wavelengths (blue, violet, and ultraviolet). Therefore, the indoor grower using artificial light as the sole source of illumination should have the flowering photoperiod start and end with an hour of light composed primarily of orange and red wavelengths. This will eliminate the problem of delayed flowering when 4000K metal halide or 6500K mercury vapor HID light (or 6500K flurorescent light) are the sole source of illumination to fuel photosynthesis.

Sodium HID light has nearly replaced incandescent light bulbs for use in night interruption lighting of field crops to curtail flowering in short day plants in the fall and winter in the Northern Hemisphere. It is also used as supplemental lighting in greenhouses, but it is not used in commercial horticulture as the only source of illumination to fuel photosynthesis because that would have the same effect as if the entire photoperiod consisted of the sunrise and sunset. It's use in marijuana horticulture is an expensive and flawed solution to the problem of delayed flowering. Incandescent light is a cheaper fix. 100 watts of incandescent light 2 to 4 feet above the tops of the plants will affect the phytochrome in 16 square feet (4' x 4'). For example, the 1000 watt metal halide or mercury vapor lamp will fuel photosynthesis in 64 square feet (8' x 8'), and 400 watts of incandescent light (100 watt light bulb per each 4' x 4' quad) will affect the phytochrome.

Here's how it works: a photoperiod of 11:30 hours would start with incandescent light to simulate the sunrise to affect the phytochrome. After an hour of just the incandescent light, mercury vapor or metal halide HID light (or 6500K fluorescent light) would be added to the light stream for 09:30 hours to fuel photosynthesis, after which the incandescent would continue alone for another hour to simulate the sunset. That would complete the 11:30 hour photoperiod. An 11:00 hour photoperiod would be handled in the same way. One hour of incandescent light alone at the beginning and end of the simulated daylength to affect the phytochrome (sunrise and sunset) and 09:00 hours of the mercury vapor or metal halide HID light (or 6500K fluorescent light) added to the light stream in between to fuel photosynthesis (daytime).

For the medical marijuana outdoor grower in the Northern Hemisphere above the Tropic of Cancer, a harvest of seedless "heterozygous" parthenocarpic marijuana should not take place until mid-November (maybe late October depending on the gene pool). In no case should a harvest of outdoor seedless "heterozygous" marijuana take place in September because that would be a fool's harvest that is not going to do much for their medical condition. In fact, it will make the whole scene a complete waste of time and energy compared to what might have been.