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formerly RGG

Does anyone know if watermelons or other cucurbits have a requirement of a minimum number of hours of darkness in order to bloom ? In other words, if a grower used grow lights all night on a plant, would he still get blooms and fruit set ? I know there are some types of plants that will never bloom if they do not receive a certain minimum hours of darkness each night for a period of time.

1/22/2012 6:31:50 PM

Sevierville,tn

good question....I never thought of that

1/22/2012 7:11:04 PM

formerly RGG

I have answered my own question. I found this on wikipedia:

"Day-neutral plants, such as cucumbers, roses and tomatoes, do not initiate flowering based on photoperiodism at all; they flower regardless of the night length. They may initiate flowering after attaining a certain overall developmental stage or age, or in response to alternative environmental stimuli, such as vernalisation (a period of low temperature), rather than in response to photoperiod".


Watermelons and pumpkins are in the same family, cucurbitaceae, as cucumbers. So if I could afford the electricity, I could shine grow-lights on my growing melon plants whenever the sun is set. And this would accelerate plant and presumably melon growth.I have used grow lights in the spring and I definitely get better growth from my plants but I think the added heat also has something to do with the better results.

1/22/2012 8:16:54 PM

Lloydminster/AB

I'd almost be 100% sure the answer on Wikipedia is correct. I'm far enough north that in June when my watermelons bloom there may only be 5 hours of what could be called dark. When the plants reach a certain age they bloom. If I get a good start that will be mid June, right when the nights are minimal.

1/22/2012 10:04:16 PM

Fenton, MI

TD: I don't think the lights will work. What i have found is after a melon is 35 days old they only grow at night.
Could be 35 to 40 days but they all do about the same.

1/22/2012 11:15:09 PM

Sevierville,tn

Whats his name has always said the more sunlight the better.

1/23/2012 8:38:35 AM

Ut

Doesn't Lloyd Bright say in his book that they only grow in the day?


It may not be that simple TD. This may be an interesting study:
Abstract
The effect of environmental factors on sex determination of flowers of watermelon (Citrullus lanatus) was studied under controlled conditions. Short days (8 h) and a day temperature of 27° C increased the tendency towards female flowers. Day length of 16 h and a day temperature of 32° C inhibited the development of female flowers.

1/23/2012 10:14:15 AM

formerly RGG

My question then would become, if grow-lights were shined only on part of the plant, would this inhibit female development on the entire plant or only on the part of the plant the light was shining on ?

1/23/2012 6:48:35 PM

formerly RGG

Here is another light related question that has popped into my head. Early on, when the days are long, it sometimes seems difficult to get female ovaries to develop. Let us say that I cover up the growing leader of the main or of a secondary or two for a few extra hours of darkness on a daily basis for a few days. Would the plant then be a lot more likely to produce early females ?

1/23/2012 7:44:10 PM

formerly RGG

I am pretty sure a watermelon will still find a way to grow if it's vine is getting extra hours of sunlight each day.I measure melon lengths a lot and I am able to notice increases both from sunup to sundown and from sundown to sunup. Marvin, you may have a good point about growth after 35 or 40 days, but I am thinking only about using extra lighting early in the season. After the vine gets to a certain size, I do not have enough lights to cover the vine and I would not be able to afford that much electricity.

1/23/2012 7:52:57 PM

formerly RGG

I have definitely answered my own question as I have 3 plants blooming right now that have been getting constant light.

4/12/2012 7:45:38 AM