What Fertilizer to Use for Giant Pumpkins & Irrigation Water Flow Rate

I'm putting this post here for my own notes.  This is something I should have done before, but it is a first time.  It is an estimate of the flow Rate of my Dan Micro sprinkler heads.  I'm using this flow rate to help me better target how much fertilizer to use.  Hard to get an exact number, because the flow through the Dan Micros wouldn't be the same as what would be coming out the end of a pipe or hose.  That is because there wouldn't be any water pressure that is created by the sprinkler heads.  I estimate a flow of about 5 gallons per minute.  I'm going to increase my watering this year as well as my fertilizers.  So this flow rate will help me figure out how much fertilizer to spoon feed per day.

The two main fertilizers I'm going to be using this year are NPK RAW Grow 7-4-5 and Cactus Jack's Citrus FeED 20-10-20.  A citrus fertilizer?  What you see on the label is often more hype than informational.  In most cases a fertilizer is a fertilizer.  The NPK rating is standardized by law.  Now there may be additional ingredients that are specifically formulated for certain plants, but typically there is not a big difference.

Ross Bowman grew three massive pumpkins this last year using a Peter's 20-20-20 fertilizer.  The 20-10-20 fertilizer I'm using early season is made by the same manufacturer, the nutrient profile is slightly different in percentages (more magnesium in my Citrus FeED fertilizer) and my fertilizer has half the phosphorous, but they are essentially the same.

I'm doing a 20-10-20 because I don't think the plants need a lot of phosphorous, particularly early is the season.  My soil tests in the spring of each year have shown that the numbers don't move down a ton.  Nitrogen and potassium numbers drop a lot in the soil by the end of the season in contrast. The other reason I'm going to use less phosphorous is Beni Meyer in his miracle year, where he grew 3 pumpkins that were bigger than the previous world record, used a 15-8-17 fertilizer (percentage wise roughly works out to a 20-10-20).  I don't know the specific reasons he used that, but if it worked for him, then it can't be a bad way to go and there may not be a build up of phosphorus in the soil over time. 

I'm also going to use the RAW Grow 7-4-5 because of the long list of micro nutrients and stimulants (growth hormones) it contains.  It isn't labeled organic, but it leans very close to an organic fertilizer.  Its nitrogen source is a plant protein hydrolysate, which studies have shown to be somewhat superior to other forms of nitrogen.  It is a little more on the pricey side, so using the Cactus Jack's helps keep the overall cost down.

In the end, it may not matter if it is 20-10-20, 20-20-20, 7-4-5, 15-8-17 or something else.  It seems these Atlantic Giant plants are special.  They seem to be able take up what they need, as long as it is available and things are kept generally in balance.  I say "generally" because if you look at soil tests of growers who have grown some really giant pumpkins you find there is inconsistency in soil pH, NPK, organic matter, etc.  So the plants seem to handle a range, but I think the key is balance.

(notes:  Cactus Jack 24 ounces per container = 48 tablespoons.  Feed 2 tablespoons per watering.)

New & Improved Put it to the Floor, Giant Pumpkin Fertilizer Program

Are you ready to rock!  That is what this new and improved 2022 giant pumpkin fertilizer program makes me want to say.  I'm excited about it. Why?  Because I think it has the answers to a question I've been asking since the first year I put a giant pumpkin plant is the soil.  How much to fertilize?  This last year I increased my fertilization, but what I found is I didn't do enough. 

As a matter-o-fact, I was still way under fertilizing I've found, based on what I've learned from other growers and seen form my own experience.  And I'm fertilizing probably not soon enough in the season.  How do I know this?  I asked the experts, starting with Utah's own record holder Ross Bowman.  At the patch tour I asked him how much potassium he was spoon feeding his pumpkins with a day?  It was double what I was doing and I was wondering if I was doing too much.  His results?  Two pumpkins over one ton each.

So the other piece of what I'm going to be doing differently in 2022 is I'm going to start fertilizing earlier.  If you've ever gone on a patch tour and saw the other guy's pumpkins and then went home and tried dumping a bunch of fertilizer on the plant in the hopes for better growth, you'll typically find it doesn't work.  Why?  Number of reasons, but one of the bigger is that the plant hasn't been primed to need it, so it is probably throwing the soil out of balance some, rather than helping.

If you've ever seen a plant mid-season that has a real nice pumpkin on it, often times the plant just seems meatier.  Like everything on the plant just wants to grow.  The stump is bigger, the vines are thicker and the leaves are often larger than normal.  Those pieces don't grow bigger unless their are the nutrients available to grow them.  It is a fine balance to keep things in the Goldielocks zone, but when it is dialed in the plant starts building bigger pipes to grow the pumpkin and the plant is primed to take on more fertilization and use it.  If you get started too late, that demand isn't created and extra fertilizers can throw things out of balance.

So in 2022 I'm going to be using the McConkie "put the petal to the floor method."  Which was the piece that I've always struggled with in the past.  In this method you spoon feed the plant with a fair amount of fertilizer until you start seeing things getting off (leaves start bloating, dark green color, maybe some brittleness in the vines) and then you start backing off significantly.  So basically you watch the plant closely and let it tell you when it has got to the point that it has a little too much and by doing so you get that plant in top gear and then brake a little before you hit the wall.  Doing it this way means the plant shouldn't lack for anything and you get that piping built for a giant.

So the following is what the 2022 Giant Pumpkin Fertilizer program looks like now.  Everything has a purpose for when it is applied.  Nutrients are given on specific weeks to address specific needs that the plant has at different times in the season in this fertilizer program.  How much is applied is somewhat dependent on your soil type, your soil report and what the plant is telling you:

Updated 3/25/22

May (focusing on the roots):
Week 1	RAW 7-4-5, RAW Phosphorous (mono ammonium), B-vitamin, liquid seaweed/kelp, compost tea (alfalfa), myco, microbes & Azos, yucca, humic acid
Week 2	RAW 7-4-5, 20-10-20, compost tea (alfalfa), fulvic acid, yucca, silica, seaweed, humic acid, foliar multi-mineral, myco
Week 3	RAW 7-4-5, 20-10-20, compost tea (alfalfa), humic acid, yucca, fish, Azos, enzymes, amino acids, iron, myco
Week 4	ammonium sulfate, 20-10-20, RAW 7-4-5, Omina, silica, fulvic acid, Azos, seaweed, humic acid, calmag, microbes, myco
June (focus on vine growing):
Week 5	20-20-20, enzymes, humic acid, RAW 7-4-5, azos, ammonium sulfate, calmag, aminos, myco
Week 6	RAW 7-4-5, 20-20-20, fulvic acid, microbes, ammonium sulfate, potassium, azos, myco
Week 7	(pollination) 20-20-20, seaweed, humic acid, RAW 3-12-12, Omina, iron, azos, ammonium sulfate, foliar multi-mineral, myco
Week 8	gypsum, aminos, TKO, humic acid, yucca, azos, potassium, ammonium sulfate, microbes, myco
July (focus on transitioning from vine growth to fruit):
Week 9	enzymes, potassium, magnesium, RAW 3-12-12, fulvic acid, seaweed, ammonium sulfate, azos, myco
Week 10	gypsum, aminos, ammonium sulfate, potassium, humic acid, compost tea, potassium, RAW 3-12-12, zinc, magnesium, manganese, boron, copper, microbes, myco
Week 11	(pumpkin gearing up), TKO, potassium, magnesium, humic acid, B-vitamins, calmag, Omina, seaweed, RAW 3-12-12, myco
Week 12	ammonium sulfate, RAW 3-12-12, cane molasses, humic acid, potassium, magnesium, calmag, iron, humic acid, microbes, myco, azos
August (focus on the fruit)
Week 13	TKO, ammonium sulfate, potassium, magnesium, RAW 3-12-12, foliar silica, microbes, seaweed, humic acid, myco, azos
Week 14	ammonium sulfate, potassium, magnesium, RAW 3-12-12, Azos, humic acid, calmag, B-vitamins, Omina, foliar multi-mineral
Week 15	ammonium sulfate, potassium, magnesium, RAW 3-12-12, foliar silica, humic acid, microbes
Week 16	TKO, ammonium sulfate, potassium, magnesium, cane molasses, fulvic acid, seaweed
September (finish the race)
Week 17	potassium, magnesium, humic acid, foliar seaweed, B-vitamins, RAW 3-12-12, compost tea, Omina
Week 18	TKO, potassium, nitrogen, foliar seaweed, foliar humic acid, cane molasses, silica
Week 19	foliar potassium, nitrogen, foliar seaweed, humic acid
Week 20	foliar potassium, foliar seaweed, humic acid