Secret Formula for Record Breaking Pumpkins: Part 2

A little over a week ago I talked about a secret project I have going to grow bigger giant pumpkins. I promised a full disclosure of what I did in my tests along with results so this post is going to reveal all.

As everyone knows carbon dioxide (CO2) contributes to plant growth as part of the miracle of nature known as photosynthesis. This enables plants to combine carbon dioxide and water with the aid of light energy to form sugar. Some of these sugars are converted into complex compounds that increase dry solid plant substances for continued growth to final maturity. However, when the supply of carbon dioxide is cut off, or reduced, the complex plant cell structure cannot utilize the sun's energy fully and growth or development is slowed down.

A Colorado State University study with carnations and other flowers in controlled CO2 atmospheres ranging from 200 to 550 ppm found that the higher the CO2 concentrations the higher the rate of formation of dry plant matter and total flower yield.

In my tests what I did is take a regular pop bottle, drill a hole in the cap and glued a bendable straw into the whole to create my CO2 chamber. I then took warm water, dry yeast and sugar and put it into the pop bottle.

CO2 is produced by yeast fermenting sugar into alcohol. Slowly the pressure will rise within the pop bottle as more and more C02 is produced so the hole in the cap and the straw produces a conduit for the CO2 gas to escape. The straw is placed over the pumpkin leaves so as the CO2 gas comes out it falls down to the leaves (CO2 is heavier than air) so additional photosynthesis can take place. Please note: the bottle will explode if you don't put a hole in the cap and don't fill the bottle more than half way full of water.

I should note that my pumpkin plants are in enclosed hoop houses so there is no wind and the CO2 is somewhat trapped within the enclosure. Otherwise most of the CO2 would probably just be carried away.

Will added CO2 by itself create a state record pumpkin? No. But what I can report is that it appeared to have an effect on plant growth. I have two pumpkin plants in each of my hoop houses. Over one plant I put the CO2 generator straw so when the CO2 came out it would fall down across the leaves. Over the 2nd plant I put nothing. Each plant that got the CO2 outgrew the plant that didn't get the CO2. It might have just been a coincidence, but in the case of one hoop house the CO2 plant was behind the none CO2 plant at the begininning of the week and in the course of one week it passed it. Again there are a lot of factors when it comes to plant growth but based on my trials there doesn't seem to be a reason to not give your plants CO2 this way.