Monday, July 22, 2019

Cooling the Plants in the Heat of the Summer

It is a hot one today.  In the three years I've been in Midway, today's forecast of 98 degrees is the highest I can remember.  When you have a plant in a greenhouse it obviously can get even hotter.  Yesterday we got to 97 degrees and the greenhouse cooling system did its job fairly well.

If you are seeing burnt leaves on your plants the best solution I've found is misting the plants during the heat of the day.  Anything over about 91 degrees and your plant isn't doing much growing.  So keeping it below that is critical to grow a big pumpkin.   In July and August, that can be hard, but some misting during the heat of the day can do the the job.  

At the old house I just used a sprinkler that could spray about 30 feet put it did it with a fairly fine mist.  You don't want a lot of water.  Just enough to lightly dampen the leaves in a way that it can fairly quickly evaporate.  I used a hose end timer to have it run at set times.

For the greenhouse I've setup foggers at the top of the greenhouse and use a Rachio controller with the Cycle and Soak setting turned on which gives me a nice mist every 15 minutes during the hot part of the day and every 20 minutes during the warm parts of the day.  

With the fans running and the foggers going I can, even on hot days like today, keep the plants about 3-8 degrees cooler (see screen shot above).   Current temperature is 96 degrees, but the greenhouse is 89 degrees currently.  Our typical summer day is about 91 degrees here and on average the greenhouse is around 88 degrees during the hot part of the day.  Which means less stress on the plant, little to no leaf burn and possibly more growth.

I'm using Jain foggers.  Fairly easy to setup and they put out a very fine mist with very little dripping after they shut off.  Like the name implies, it looks like a fog when there is no wind and if you run them long enough.

Wednesday, July 17, 2019

Latest Pictures from the Patch

I've been a little slack on the posts lately.   Pictured here is the 2005 pumpkin (AKA Uncle Sam).   This pumpkin I think is shaping up to have the 2005 ribbing and the 2416 coloring, which if it is true, could be ideal in terms of looks.  I've never had a better looking plant in mid-July than this one.   Great color, the leaves are all in great shape and the plant looks healthy.  The root system also appears to be impressive.  I see roots all over the place.

Growth hasn''t seemed to be matching the beautiful plant so I sent in a tissue test to see what was going on.  In my spring soil analysis potassium and phosphorous were very night and nitrogen was low.  When doing my EC testing the numbers consistently came in under the ideal, so the natural assumption, since sandy soil leaches nitrogen easily, is that nitrogen would be what was missing.  So I've consistently been adding nitrogen throughout the season in spoon feeding amounts.  Only in the last 1 1/2 weeks have I seen the plant react in such a way with bigger leaves and darker color to indicate that the nitrogen was making much of an impact.    But in the last 1 1/2 leaves the leaves did go a bit jungley.  Gotten noticeably taller, darker and with bigger leaves.  But as you can see the leaves don't have that overly bloated, blue color when the nitrogen has gotten to be too much.

I have been adding potassium and phosphorous in much smaller amounts as compared to nitrogen over the last two months.  I was a bit surprised by the tissue sample results however.  Nitrogen was very high in the tissue and potassium and phosphorous were a bit low.  What!?   Didn't see that coming because my soil was just the opposite back in April.  So probably for the next month I'm not going to be doing any nitrogen and possibly do some foliar potassium and phosphorous in the form of TKO along with soil applications. 

I'm wondering if the nitrogen has been the inhibiting factor to this point, because of too much.  It will be interesting to see if as things come more into balance if the growth curve will improve.

Wednesday, July 3, 2019

How to Know How Much to Fertilize a Giant Pumpkin

One thing that is critical, but kind of difficult is to know how much to fertilize a pumpkin plant for maximum growth.  This is kind of something I don't feel I've fully figured out, but something I think I'm starting to get a better idea on.   In my experience there are four ways to know how much to fertilize a plant.

First, is a soil test.  A good professional soil test can let you know exactly what you have in your soil and can give you some idea of what you need to add.  One challenge that can come from a soil test is knowing how much of the nutrients in your soil are actually available to a plant.  For example, your test may show you have a lot of calcium and a lot of potassium.  The question is how much of that is in a form that a plant can uptake and is having too much potassium affecting the plant's ability to uptake the potassium.   A soil test is crucial, but doesn't give all of the answers and unless you are testing frequently, it doesn't tell you how the numbers are changing as the season goes on.  It is more of a one-time snapshot.

Second, leaf tissue test.  The nice thing about a leaf tissue test is it tells you what is in the plant (more accurately, what is in the leaf), so it gives you a better idea of what the plant is up taking and what might be deficient.  So in some ways more accurate than a soil test, but the two go hand in hand in a lot of ways.  A lot of growers will get a tissue test around the time they pollinate.  It is kind of expensive, but a great way to know exactly where your plant is at.

Third, EC testing.  Using a little EC testing unit it can tell you about what the fertility of your soil would be based on its conductivity.  Most of the macro nutrients are in a form of a salt, which conducts electricity.  So you shoot for a range and it will give you an idea of where you are at with macro nutrients in the soil at a given time.  The nice thing about EC testing is you can do it frequently and then make adjustments accordingly.  The downside to it is that it doesn't tell you if you have too much of one thing or not enough of another.  You just get one number for everything.  My soil is sandy, so nitrogen leaches easily.   If my number is low and my soil test said he was a little high with phosphorous and potassium then I an assume that my nitrogen is low.

Fourth, is the eyeball and experience test.  Plant color, growth and what the vine tips are doing can give you good clues to what your nutrients are doing for you as well.  It can be a little tricky at times because yellow leaves can be caused by a lot of things, but where and when the leaves yellow are excellent clues to potential issues.  The downside to the eyeball test is that you usually get information a little too late.  Only after the problem occurs.  But if you can't afford to tissue test, weekly, it is the next best thing. 

The best solution is a combination of all the above.  The right testing at the right times will give you the information you need to grow a big pumpkin.

Monday, July 1, 2019

Biologicals for Giant Pumpkin Plants

Today I gave all of the plants biologicals such as beneficial bacteria and fungi to help to protect the plants.  I sprayed Actinovate on the leaves and on the soil which helps to protect the leaves from things like powdery mildew and soil born diseases. Then on the soil I also sprayed azos and Biotamax (tricoaderma & bacteria).  This time of the year the soils are warm and moist.  Perfect conditions for the bad guys to try to take over the biology of the soil, so in theory, adding the good guys to the soil helps the good guys dominate as well as protect and feed the plant. 

One thing I recently read was the idea of how the soil near the new growth is exposed to the sun so it dries out faster, but the soil under the leaf canopy says moist because it is shaded.  So the challenge is not over watering the stump area while under watering the out edges of the plant.   I don't have a great solution for this, but something to think about.

One other biological I add while burying the vines is mycos to each leaf node along with granular seaweed, azos and humic acid.  Just a pinch at where the roots come out at each leaf node. 

Not since my 1421 plant from years ago have I had so many roots popping out of the soil on my 2005 plant.  In particular I can tell these roots are coming off the side vines.  I may be over watering some (I backed off a little on the water today--hard because of the temperature swings), so that could be why, but I hope it is because this plant has vigorous root growth.  The plant seems very happy.

The 2005 plant has been terminated on about 1/2 of its growing space.   I would guess I'll have it terminated 90% by the middle of July.   In about 2 weeks from now that pumpkin should be taking off.

The 2255 plant has a lot more room to grow.  On one side it is about 25% terminated.  On the other side it has a fair amount more room.  I'll let this plant grow as much as I can, because the old leaves on the plant are already hammered, so I'll need new growth to power the pumpkin.   It has only taken up about 35% of its available growing space.