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Sacramento, Ca

Don Langevins book "How To Grow World Class Giant Pumpkins II" has a feeding schedule on page 75. It says that the first four weeks of plant growth that the plant should be fertilized with a fertilizer high in phosphorus. On Hollands web site they have a feeding schedule and their schedule says to feed a high P fertilizer starting June 10th. My understanding of P is that it promotes strong roots and blossoms. Is there any harm in feeding the plant a high P fertilizer in the first four weeks, and by that I mean, any problems that will show up down the road rather than right away? I have been feeding my 1462 Gibson with Super Bloom 12-55-6. The plant is 4 weeks old and besides the stuff I added to the soil, in 4 weeks it has had 5 tablespoons of Miracle Grow 24-6-18 and six tablespoons of Super Bloom 12-55-6. My soil report said that my P was 40 ppm weak bray (very high). I have not seen any ill affects yet. You can see pics in my diary. I also have a comprehensive diary here; http://www.midnightgardenerblog.com/forum/m-1237731981/s-all/

5/24/2009 12:51:30 AM

Ct

I read the same thing. Good question.

5/24/2009 4:54:36 AM

Denver, CO

There is some considerable debate as to the damage done to Myco and increased amounts of water soluble P.

It seems very likely that high amounts of P, in any form, and almost certainly in a water soluble form will keep Myco from properly infecting your plants roots. (at 100 PPM or more, no development of Myco will form at all.) As a very good grower told me, high P tells the Myco "your not needed here" and the Myco gets sad and fails to do its thing.

Others, here on this board, would disagree strongly with what is said above.

Ironically, one very important benefit of Myco is increased P uptake, allowing greater root mass.
I have written to RTI twice on this very dichotomy with no response from them. Seems very likely that its true. A Colorado State University agriculture expert has confirmed it in numerous field test.


Thus, you are left between deciding if Myco development and its related benefits are better, or if added P earlier on in cold soils is better. If you have warm, 65 degree or above soil, favor the Myco development. If its colder soil, decide what you think is best in your mind.

I have two plants, one I used the soluble P on and the other the Myco. So far the soluble P plant is way ahead. BUT, that not to say down the line the plant would not have been better off with early Myco infections. Lots of really big pumpkins are being grown with Myco treated roots!

Here is link to the debate, which I accidently posted on the wrong board a couple of weeks ago.


http://www.bigpumpkins.com/msgboard/ViewThread.asp?b=3&p=299631

5/24/2009 6:26:29 PM

Sacramento, Ca

ghopson; Thanks for the link, an interesting read for sure. However, I am not concerned about whether the Myco inhibits the P uptake, rather, I want to know why two different AG experts recommend two different things when it comes to what point in the growing process that you add P to the soil. My high school biology tells me that Don Langevin is wrong. Having said that, I did what the book said and have been adding Super Bloom 12-55-6 on a weekly basis. I have seen no negative affects so far but it does look as if I am getting male flowers already near the base of the main vine.

5/25/2009 11:41:32 AM