Solar activity - Why we may have to adjust growing habits


But, regardless of the causes of climate changes or whether we can do anything about it, the trajectory suggests that we will have to make adjustments to our growing habits whether as it heats up or as it cools off.

Solar Update June 2017–the sun is slumping and headed even lower
June 6, 2017

Solar cycle 24 has seen very low solar activity thus far, likely the lowest in 100 years.
Essay by David Archibald

Figure 1: F10.7 Flux 2014 – 2017

The F10.7 flux shows that over the last three and a half years the Sun has gone from solar maximum through a bounded decline to the current stage of the trail to minimum. Solar minimum is likely to be still three years away.

Figure 2: F10.7 Flux of Solar Cycles 19 to 24 aligned on month of minimum

Solar Cycle 24 is sitting at the lower bound of activity for solar cycles back to 1964, the start of Solar Cycle 19. From here to minimum though, it looks like Solar Cycle 24 will have much lower volatility than the solar cycles that preceded it.

Figure 3: Oulu Neutron Count 1964 – 2017

According to Svensmark’s theory, the neutron flux, with its effect on cloud cover and thus the Earth’s albedo, is one of the bigger climate drivers. For Solar Cycle 24, the neutron flux duly turned around and starting rising again in 2015, one year after solar maximum. It is a safe bet that the neutron flux is heading for a record high at solar minimum (+ one year) relative to the instrumental record.

Figure 4: Oulu Neutron Count aligned on month of solar minimum

The last weak solar cycle was Solar Cycle 20 which caused the 1970s Cooling Period. From the same stage in that cycle the neutron count flattened out to minimum. That could happen for Solar Cycle 24 but it is more likely to keep rising to minimum as 23 did and thus we can expect a count, at the end, of over 7,000.

Figure 5: F10.7 Flux and Oulu Neutron Count 1964 – 2017

If we conflate the F10.7 flux and the Oulu neutron count inverted, that shows they tracked each other closely up to 2004. Something changed in 2004 and since then the neutron count has been higher relative to its previously established correlation with the F10.7 flux.

Figure 6: Ap Index 1932 – 2017

Figure 6 shows that what changed in 2004 was the magnetic output of the Sun, shown in this instance by the Ap Index. Prior to that, there seemed to be a floor of activity at solar minima, just as the floor of activity for the F10.7 flux is 64. Three years to minimum and the Sun is now back to that level.

Figure 7: Solar Polar Field Strength 1976 – 2017

The best predictor of the amplitude of the next solar cycle is the strength of the solar polar magnetic fields at solar minimum. Figure 7, from the Wilcox Solar Observatory, shows that the solar polar magnetic fields at minimum have been weakening with each successive cycle.

Figure 8: Solar Polar Field Strength aligned on minimum strength at solar maximum

Solar Cycle 25 started from the blocks looking like it was going to be very weak and fulfill the prophecies of those predicting a Maunder-like experience for the 2020s. Then after a couple of years it caught up with Solar Cycle 24. Looking back over the previous three cycles, the solar polar field strength at this stage, three years before minimum, has been close to the value at minimum. On that assumption, Solar Cycle 25’s amplitude is likely to be two thirds of that of Solar Cycle 24, and thus 60. Further climatic cooling is therefore in store.

Figure 9: Sunspot Area 1985 – 2016

NASA has deigned to give us another nine months of sunspot area data by hemisphere, up to September 2016. The strong asymmetry between the northern and southern hemispheres continues. The fact that the hemispheric peaks of the last three cycles align indicate that there is a multi-decadal force operating in the vertical dimension. The chance that two sets of three points line up exactly by themselves is infinitesimal.

Figure 10: Hemispheric Sunspot Area and F10.7 Flux

As shown by Figure 10, total sunspot area tracks the F10.7 flux closely.


At the same time, our planet’s capacity to store solar energy has increased. Consequently the decreasing output from the sun is a wash, and actually a bit of a reprieve from the nastiness ahead.

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Maybe momma nature is giving us a chance to prepare.
This has been a cold spring or maybe described as a warm late winter :wink:

But with the wild swings it kind of reminds me of…

The fella who had one foot in a bucket of boiling water and the other is a bucket of ice…




That’s in your area! :cloud_rain: :snowflake: :wind_blowing_face: :cloud_rain:


The only constant to Kentucky weather is volatility and unpredictability. We had 40* and 90* highs in the same week. Maybe decreased solar output will make the grass grow​ slower. I hate mowing!

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Yup !!! Here . And in…

and …

The above are are out of the ordinary events in comparison to the last 40-60 years.

So some areas are hotter and some colder… hence the two bucket example.

All I know that this is my second year of no plums/aprium/pluots (except a very marginal Santa Rosa crop). Luckily my peaches/nects threaded the needle this year.:cry::sob:



I’ve gardened a long time and if you are not prepared for the predictable unseasonableness of weather, shame on you. Out-of-the-ordinary weather is the norm. You gotta have strategies in place whether it is protecting your peppers from sunburn or your tomatoes/fruit from frost. Weather happens.


Yeah the high water levels is messing me up. I can’t bring my car to my cottage on the caravan this year because the high water is making it impossible to unload the cars on the island. The boat is too high up. Only pick up trucks and high SUV’s can make it. I have a van. Oh well, I haul everything by hand. Including shingles for my roof! Argh! The freighter’s are happy they can load to maximum.
Temps have been below normal a long time around here, over a year. We are at last hitting the 70’s here. I had a fire last night at my cottage, it was in the 50’s. My only heat up there is a wood stove. Works great! A new modern one with high efficiency. The low tonight is 53F. Not exactly June weather. Just like last year too. We are double digit below normal. Next week a warm up is expected. Good I’m usually swimming by now but the water has yet to hit 60F.

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I met a distant cousin last week for lunch at a waterfront restaurant on the Potomac River, Washington D.C.
Just in the last couple of years they installed huge, movable flood gates to protect all the restaurants and shops from now- frequent flooding. I lived in DC for thirty some years and never saw anything like this. Same flooding happening in Annapolis, Md and Alexandria, Va. Va. folks are studying Dutch flood control systems- they are state of the art.



Peppers, tomato’s sure. But how do we protect against blooming followed by weather that is too cold and wet for the polinators to come out. My Toka plum tree was a solid wall of flowers. I counted six ( yup 6) plums on the whole tree. And they are supposed to be zone 4 Hardy. I guess it’s not how cold you make them but how/when you make them cold.

But thank G-d for the peaches.

BY THE WAY BELOW ARE:. … First leaf on the left … third leaf on the right and first scaffold in the center



You are so right about it not being always about how cold but when. I have a Toka in my zone 2 yard, and it lived the winter just fine, no dieback , it was full of blossoms and I do believe it has set some plums. In my area the plums do not wake up until late so they do not suffer the waffling warm/cold temperatures. Go figure, my zone 4 plum set fruit and my zone 2 grape right near it had lots of dieback. :confused:

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The U.S. is only 1.84% of the earth’s surface.

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Oh beautiful picture Mike .What treasures you’re holding.

Your post got me thinking. As a gardener, most things I crop do not need pollinators - potatoes, carrots, swt potatoes, beets, yacon, cabbage, cauliflower, romanesco, brussels sprouts, broccoli, kohlrabi, garlic, onions, asparagus, celery, pak choi,lettuce, chard and tomatoes and peppers are self pollinating so I haven’t thought much about pollination until I more recently got some fruit trees. Actually I’ve grown elderberry many years - but it blooms late. So cukes and (new to me) watermelon are it.

I thought cold hardiness referred to the temps the tree could endure, and pollinators are a separate issue. Anyway, my point was about the ability of man to ‘fire and adjust’. If the weather is determined to be unfavorable to pollination I’d do it myself (my point above is that it never was a problem for me but now it IS on the calendar)
So my ‘fire and adjust’ strategies are for this next season: paint trunks white to possibly delay bloom, have ammonia spray or other frost protection ready, subtract 8 points from the weatherman’s overnight low predictions in the spring, esp if it was a sunny blue sky day before. If I don’t do these sensible things, shame on me.


I agree local weather tells us nothing. I would say the sun is everything though. Also the change in the Axis angle caused by that earthquake in Japan also is a major influence. Overall we have not been warming, not for 20 years. At least according to NASA satellite data. So I suspect with this lull we will see some dramatic changes. The last time the sun had this low of sun spot activity we had a mini ice age for about 70 years.So this is a very big deal.

Richard Harrison of the Rutherford Appleton Laboratory in Oxfordshire told the BBC.
‘I’ve been a solar physicist for 30 years, and I’ve never seen anything like this.’
He says the phenomenon could lead to colder winters similar to those during the Maunder Minimum.'There were cold winters, almost a mini ice age.
‘You had a period when the River Thames froze.’

Professor Valentina Zharkova disclosed at the National Astronomy Meeting that a mini ice age may soon be upon earth. The scientists claim that their research has a 97 percent accuracy rate and that the mini ice age will result from something called the Maunder minimum effect.

These are real scientists, not guys with useless Bachelor’s degrees in climate science.

The good news is full affects of this will not happen till 2030. Grow’em if you got’em! While you can!

I mentioned all this over 5 years ago, but too many want to make it colder, which is crazy! Burn a tire, save a tree!


I am growing Carmine Jewel in 7a… I figure it is a safe bet.


Telegraphic summary: always grow things that have a climate range such that your zone is right in the middle of it.
If you are in Zone 6, stuff listed as Zone 5-7, or 4-8, is what you want.

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But not unique in the world. I am sure that there are other parts of the globe that have had a hotter, dryer or colder wetter weather season.

The above notwithstanding and without getting into any type of “long term climate change” conversation, what I am noting is that:

  1. there are indications that the current solar weather (climate) may indicate a period of lower temps ( not necessarily long term global “cooling” or “warming” ) like we had in the 1970’s.
  2. that this period may last for a non-geologically significant period of time as measured by our own fruit growing lives.
  3. that we may have to take steps to adjust our methodology in growing fruits, especially those of us who are in areas like the northeast. Here in the Northeast, regardless of the zone hardiness of the variety, we are dealing with very narrow windows of time during which it does not take much of a swing in temperature to wipe out a whole crop. These swings can: kill the dormant buds, semi-dormant buds, swelling buds, open flowers, or once the flowers are open, cold weather that keeps the polinators at bay.

Any weather changes that indicate even a relatively short period “trend” are things that we need to take into account in our orchards.



Mike, what I’m saying is that the current ebb in the solar cycle might be offset by increased heat retention in our atmosphere. Further, climatologists consider the recent increased volatility in the weather as a result of overall higher concentrations of CO2.

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Got it.


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Thanks for sharing this, Mike.

Considering the Eastern US is a typically erratic spring weather climate (unlike the evolutionary homeland of most temperate fruit trees), and likely just getting more erratic, the natives that bloom later will likely always be a surer bet. I love apples and pears and stonefruit, but more and more I realize the value of persimmons, pawpaws, aronia, elderberry, chestnut, hybrid hazels, etc.