Creating hermaphrodites

I am growing hydroponically using a 400-watt metal halide lamp for vegetating and a 1000-watt HPS lamp for flowering.
Everything goes fine in the veg room but when I flower everything turns seeded. About two weeks after entering the room, the females start showing that they were pollinated and start forming seeds. No matter what strain I try, this happens. I was growing in another location for seven years and this never happened.

I thought the pollen might be left over from a previous tenant who had grown. I’ve washed the rooms down and ionized them to no avail. Why is this happening and what should I do to stop it?

NJS,
Denver, Colorado

Only one plant need be affected for all the plants to be pollinated so you should check carefully to find an offending plant. That could be the end of your pollination problems.

Frequently plants turn hermaphroditic in response to stress. I assume your gardening practices in the new space are close to those in the old. That leaves the change in the environment as a possible cause of this phenomenon. I would guess that either the plants are undergoing heat stress from peak temperatures soaring into the 90’s, or light stress from irregular lighting cycles or stray light is affecting your plants.

To check for heat stress, place a recording thermometer at plant canopy level to note high and low temperatures. If the peak is above 80 degrees do something to cool the garden. Options include air-cooled lights, ventilation and air conditioning. To check for light pollution, stand in darkness outside the room while the lights are on inside the room, and observe any light leaking through. Seal the leaks.

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