Several questions

[Gimme3]

First of all, i'd like to say how Wonderful it is to learn so much more than i ever came across anywhere else...jus listenin an reading your Scientific posts presented in a fairly down to earth manner....Mr. Tom Wagner. I am truly in awe of your life's work of 54 years, an so grateful you take the time an effort to Moderate an answer questions here....TY

As my potato-planting season approaches...several questions or things that i jus dont know for sure yet...make their annual creep back into my thoughts....interested in All opinions...here goes...

#1...i always wonder....which scenario is advisable for highest yield. Average last frost date here is April 15. Zone 7b or 8a

Scenario A = get seed potatos in-ground around 2nd or 3rd week in March, get an early start on them before June soil heats up. This scenario quite often leads to having foilage damage from a early April light frost...but the plants recover an do well, i'd say. Hilling does minimize exposure, but i have always understood that its not advisable to cover all foilage.

Scenario B = wait till the first week of April, be mostly immune to frost damage by the time shoots come up...continue as above, but have a later harvest, an a greater chance of having to hand-pick Colorado potato larvae off.

The crux of this question is this ...does the energy demanded from the seed to restore /regenerate foilage after a frost...curtail in the long run...yield... in a significant amount ?

#2...some long-time growers in my area have told me that if i tried to save and re-plant smaller tubers (as in tubers that didnt mature simply due to the fact that it was diggin up time)...that these tubers would NOT produce plants that in turn would develop a consistent crop of mostly normal-size potatoes. In other words, all i'd get the second time around would be small potatoes, ...even if i planted ..say...a egg-size whole potato. What are the Facts...regarding this ?

#3 Lets say i wanted to grow a particular CV of potato and retain some of it for future re-planting, across the foreseeable Seasons to come, and...assuming good rotations and cultural practices, disease is not a current issue. What would be the Best practices to adhere to, regarding tuber selection for saving, and Most importantly....storage conditions if i wanted to keep it a viable and healthy seed potato for the next 9 months ?

Appreciative of all opinions an experiences on these Matters...)))

[Tom Wagner]

Gimme3 says..

#1...i always wonder....which scenario is advisable for highest yield. Average last frost date here is April 15

Mother Nature controls nearly all environmental factors such as temperature,rainfall and sunlight; therefore the grower, as "Kid Nature", often relishes the power control of when to plant. The grower is so consumed with his/her superstitions, habits, and spring fever, that planting time is rarely controlled by carefully acquired scientific knowledge.

Funny coming from a person who fancies himself as The Artist, previously known as The Scientist. Half-time jokes aside; What are some of the factors optimizing yield, despite frost damage, heat, and insects?

Frost Damage:

The danger of frost is the major "Worry" factor in determining planting date in most production fields and gardens. It is not uncommon to see pockets of frost that will destroy some or all of the foliage after plant emergence. You may see it only in lower areas of a field. Frost damage often has negative impacts on yields. If you increase the time between re-emergence and row closure, that extra time directly reduces the bulking of the tubers. A freeze that burns the plant down below the soil line could cause branching of the sprouts. The multiple vines thus often results in an increase in tuber set (counts). Smaller tubers may mean lower yields. Variation in the date of renewed emergence of individual plants obviously affects over-all yield.


What can you do to get an “optimum” planting window during which conditions are best for producing the highest potential yield in your location and season?

Buy a temperature probe. If the soil temps at 4 inches below the surface is 40 F. it is probably best to wait until the soil temps are 45 to 50 F. or even 55 F. If you expose the cut tubers to stresses, such as unfavorable soil conditions, (wet soil and cold temps), the emergence of the potato plants taking 30 days or more are related to reduced yields due to seed decay and Rhizoctonia stem canker. Colder soils result in shorter plants, smaller leaves, fewer stems with fewer tubers subject to brown center developing into hollow heart as the tubers grow. The longer it takes to coalesce the row; the lower the potential yield.


Early planting, especially in Georgia, can help establish the crop during periods more favorable for attaining the best tuber quality. The tuber bulking stage has to get past the time when daytime temperatures usually start to climb. In Georgia, when the night-times stay above comfort levels, the tuber doesn't set the higher gravities associated with high tuber quality. It is a respiration burn factor that favors potato production where nights are cooler. The potatoes need a "rest" otherwise it is like they are up and running all night!

No two seasons are ever identical . When most potatoes are planted, a fight begins between the organisms that are infecting the cut surface on the seed piece and the tuber attempting to heal the injuries. If you use cut tubers , try to get the cut seed size close to 2 oz. That way the seed piece has enough energy and nutrients to last a while after emergence. Hopefully, the cut tuber piece will remain sound until the plant has a chance to utilize all the nutrients and energy stored. Planting fresh cut seed into soil that is below 45 F. nearly stops wound healing, and greatly increases seed decay. You may get Rhizoctonia stem canker, causing damage by girdling sprouts, stolons and roots of the potato plants. Planting whole "B" size tubers is a great practice. No cuts, fewer problems.

Some potato varieties are even more sensitive to delayed emergence under unfavorable conditions. Sprout growth rate has been studied directly tied to soil temperature from 45 to 70 F. But dry soils, insufficient nutrient availability, and compaction can all worsen the effect of cold soils, further delaying early plant development. The main thing is to try to get tuber bulking started when the soil temps are above 55 F. Planting early maturing, mid-season, and late maturing potato varieties will have direct (or inverse relationships) to yield when planted early versus delayed. I could go into all sorts of scenarios on that issue.

#2...some long-time growers in my area have told me that if i tried to save and re-plant smaller tubers (as in tubers that didnt mature simply due to the fact that it was diggin up time)...that these tubers would NOT produce plants that in turn would develop a consistent crop of mostly normal-size potatoes. In other words, all i'd get the second time around would be small potatoes, ...even if i planted ..say...a egg-size whole potato. What are the Facts...regarding this ?

Somewhat complicated. If the previous crop of potatoes were infected with any number of potato virus strains, it wouldn't matter if you planted cut pieces of large tubers OR planted intact smaller tubers. Virus infected potatoes notoriously produce crops of smaller yields and sizes.

But if the crop was not infected, but the storage of your tubers was less than ideal,(dessication/early breakage of dormancy) the resulting spouting of all the eyes and spent energy of the tuber may produce less yield. Multiple stems means more tubers per plant, thus smaller tubers. It is usually a good idea to plant whole tubers at a greater distance apart to accommodate for the extra stems.

#3 Lets say i wanted to grow a particular CV of potato and retain some of it for future re-planting, across the foreseeable Seasons to come, and...assuming good rotations and cultural practices, disease is not a current issue. What would be the Best practices to adhere to, regarding tuber selection for saving, and Most importantly....storage conditions if i wanted to keep it a viable and healthy seed potato for the next 9 months ?

Tough issues there for sure. I am lucky I have cooperators willing to allow me to store my tubers for planting in near state of art storages. I had extreme difficulties maintaining tuber quality for replanting when I was on the farm south of Lancaster, Kansas. The long storage from July until March in a potato cellar was not conducive to maintain good yields on repeated years of saving my own stock. It allowed me, however, to breed for more vigorous varieties and I am forver grateful for that. In those days I planted the tubers whole since they were so dried out and had sprouts many inches long. You may find yourself very frustrated like I was. If you can access a storage facility that can be kept at 40 F or cooler with ample humidity, go for it.

As regards to later plantings of potatoes and insect pressure...

a greater chance of having to hand-pick Colorado potato larvae off

I remember as a kid hiring myself out to pick CPB off of potato leaves at a penny apiece. I am in a growing area lucky enough not to have the Colorado Potato Beetle. Your battles with the CPB will remain your own. I do breed potatoes for enhanced tolerance to insect pest pressure by incorporating higher alkaloid content in the leaves, but not in the tubers. Seems to help. I also breed potatoes to have an extra hairy trait with trichomes that exude stickiness droplets which offer both a physical structural barrier and a sticky trapping mechanism.

.....how Wonderful it is to learn so much more than i ever came across anywhere else..

That is quite a challenge to try to uphold! If I can personally learn more by attempting to answer your questions, then I am a life-long student of learning. If you have learned anything from my self-professed odd style
of the English language, it would make me by default; the teacher.

Tom Wagner

[Gimme3]

Mr. Tom Wagner wrote

"That is quite a challenge to try to uphold! If I can personally learn more by attempting to answer your questions, then I am a life-long student of learning. If you have learned anything from my self-professed odd style
of the English language, it would make me by default; the teacher. "

LOL...not at all a challenge for you, there in this particular Field...i know good an well you dun Forgot more about potatos than i'll ever even come close to learnin...))) Bocephus sang a Live version of "Country Boy Can Survive"...in which..as he was wrappin it up, he ad-libbed..." We are TOURISTS.....We are GUIDES". yeah,...we all are one or the other, sometimes...an sometimes we are both things at once...))) Learned a lot from your answer...TY. Got a few follow-up questions.

I'm gonna apply your advice and monitor soil temps at 4" depth and shoot for a planting to occur when minimum fluctuation temp is 50`F across 2-3 days and expected to be fairly stable...which means propably 1-2nd week of April, maybe the 3rd. Is 4" the depth at which you advise planting the seed potato ? Seems like i usually go about 6-7 inches deep...maybe i need to shallow that up, some.

The tuber bulking stage has to get past the time when daytime temperatures usually start to climb. In Georgia, when the night-times stay above comfort levels, the tuber doesn't set the higher gravities associated with high tuber quality

Is there any stage after the tuber-bulking stage..other than Harvest ? I take it the tuber-bulking stage is the period when formed tubers swell and grow out to maturity..is that correct ? Additionally...what would be ideal soil temp Comfort range at night , and at what upper fluctuation soil temp in Day... cause limited tuber-bulking? To some degree , mulch selection/application will depend upon insights gained thru these questions/answers.

I do employ the sprouting or "chitting' practice, but i have never allowed any cut-curing, prior to planting sprouted cut seed. Would that be advisable/helpful ?

Regarding ideal storage conditions for holding over seed potatoes...how bout in a plastic bag in the lower lettuce drawers of a refrigerator ? I have a second refrigerator just for garden and game use. Any ideas to store them well, there, are sho appreciated.

As for the Colorado Potato beetle, and the Mexican bean beetle on my beans...2 years ago i first noticed new bugs i had never seen in the garden...and was able to identify them as Predatory Stink Bugs. I have seen one eating a CPB larvae...and for sure...my CPB outbreaks have been quite easy to manage in the past 2-3 years...all it takes is noticing them upon first arrival and promptly killin them. It wasnt always that way tho..an i guess any Season could have a strong outbreak..over time. I've had one or 2 Real bad years ...across about 12. A Real problem that sho rowls me up is the Fire-ants that love to build a mound right on top of a Potato plant and suck the tubers and vines dry. I use my own custom-made Spinosad baits , as well as spot ground saturation, to keep them in check, but it's a never-endin battle. It'd be great if you found a way to breed a fire-ant resistant potato...)))

I sure Thank Ya for the educating, informative replies...Tom Wagner...and again...others w/opinions and related experiences...feel free to chime in...)))

[Tom Wagner]

Gimme a break, or two, or three,

Headline: "Country Boy Can Survive"..on potatoes!

You seem to allude that I have forgotten more than you know about potatoes and that, my friend, is implying that my artifices are but illusions.

Punning intended, if you doubt my veracity, I'll show you artifist! with one finger...oh never mind..('')

Joking drawn asunder, many potato growers will plant shallow in the earliest plantings, only to harrow off the top inch or so of the soil, to hasten warm-up and earlier emergence. So yeah, 4 inch planting depth is OK, followed by raking the top layer off a bit, and then hilling up as the plants are just starting to emerge. I wish I could show you pictures of the pros and cons, likewise the coulda, shoulda, and didda or such actions.

Is there any stage after the tuber-bulking stage..other than Harvest ?

Yes, of course! The tuber bulking stage implies just that. This makes sense, as the time when the bulk of the tubers form and fill out. This is followed by a slowing down of the expansion of the tuber but increases of specific gravities. This second stage in one fraught with hollow heart disorders, especially in times of great fluctuations of temps and moisture. The next period is one of senescence, whereas the plants begins to yellow and transfer nutrients to the tubers. The skin begins the process of fixation. Most growers speed the later stages by killing the vines.

Additionally...what would be ideal soil temp Comfort range at night , and at what upper fluctuation soil temp in Day... cause limited tuber-bulking? To some degree , mulch selection/application will depend upon insights gained...

Potatoes do quite well with fairly hot days if followed by cool nights. I am talking about chilly enough to almost needing a jacket when the sun go down. That is where coalesced rows prevent the sun from super-heating the very surface of the soil. Those cool nights rapidly cool off the top 1/2 inch of soil, bringing it closer to sub surface temps. Those hot Georgia nights prevent the top layer from cooling off quickly and the foliage is panting like a tiger on hot sauce! You want the leaves of the potato to regain turgidity.

but i have never allowed any cut-curing, prior to planting sprouted cut seed. Would that be advisable/helpful ?

Because I plant so many potatoes over a 5 month period.. I cut a lot of potatoes and allow them to cure even if they already have a lot of sprouts. It also gives me data on rot resistance in my breeding work and selection. That doesn't mean I don't plant immediately after cutting either.

Regarding ideal storage conditions for holding over seed potatoes...how bout in a plastic bag in the lower lettuce drawers of a refrigerator ? I have a second refrigerator just for garden and game use. Any ideas to store them well

The tubers stuck in a crisper often freeze due to lack of air circulation. To keep them from freezing, you may have to keep the temp set higher and that defeats the idea of perfect holding temps. Lots of luck on this one.

Predatory Think Bugs

We need more of these bugs that think for us and go after what we think we don't want. Think Fire Ants..Go Preds!

others w/opinions and related experiences...feel free to crime in..

Partners in chime, all the time, get in and rhyme, and don't be a mime!

Tom Wagner

[feldon30]

I didn't know it was preferable to use small seed potatoes and avoid the whole cutting process.

I have some smaller and some larger. The larger I will cut in 1 1/2" pieces and let them scab over for a day or two and then toss them all in wettable sulfur, like the instructions I've read say.

Should I spritz the potatoes with a spray bottle of water (or other goodies like kelp emulsion) at any point?

Next time I will try to get all small tubers so no cutting is required.

[Tom Wagner]

In the past, buying pre-sized B tubers for planting was an expensive premium, but with increased demand, many seed growers customize their crop by planting closer and vine killing sooner in order to maximize the 1 7/8 " to 2 1/2 sizes. The Netherlands really emphasize this habit since they export much of their seed potatoes to developing countries where seed cutting machines are not available, or stand losses are problematic in cut potatoes.

Diseases spread rapidly when seed potatoes are cut. Rot takes its toil in the ground. I have to sterilize my knives in chlorine bleach between varieties of potatoes. I have to build up many of my potato clones rapidly at times, so I have no choice but to do this cutting. I also need to evaluate clones for their propensity to tolerate seed cutting.

I have used many types of seed potato dusting over the years. I have used gypsum, lime, sulfur, Product 21(minerals) fir bark, etc. I don't spray water on the cut potatoes, but I suppose a kelp spray is OK. Conventional fields offer many fungicides that mostly are not available to the home gardener.

[feldon30]

Thanks for the info. Will def. look for smaller potatoes next time.

And dipping the knife in bleach and then rinsing it off between potatoes is work.

[Gimme3]

Tom Wagner...pleased to find a another common appreciation we both have...one for good Outlaw music...

Implications are not always what they seem To state that what you have forgotten about something is more than i'll ever learn about it implies the great confidence i hold in what 54 years of practice and actual occupation has taught you, versus what i might learn in this single area thruout the Time ahead. As to veracity...i must say...your wit and punning are enjoyable diversions , necessary to be contemplated seperate from the habitual observances of Scientific truth given in your answers.To me...asking you a potato question is like gettin good inside tips down at the horse track...when answered.

Gettin close to placin bets time, here...got one more area of inquiry. Senescence...the beginning of leaf yellowing and skin thickening...when a grower notices the onset of leaf-yellowing occurring and induces foilage kill...how long do they then leave the crop in the field prior to digging ? Is the foilage kill rapid ..as in complete within 24 hours ? Can it be suitably practiced by simply cutting them down, or are herbicides always used, as opposed to mechanical means ?

8) Rhyme....Tom...an i think i can apply a little artifice..myself..on that refrigerator storage idea...Thanks for the Answers...)))

[Tom Wagner]

Gimme - a response,

..when a grower notices the onset of leaf-yellowing occurring and induces foilage kill...how long do they then leave the crop in the field prior to digging ? Is the foilage kill rapid ..as in complete within 24 hours ? Can it be suitably practiced by simply cutting them down, or are herbicides always used, as opposed to mechanical means ?

Commercial potato growers seem to always ask me, "How many days maturity is your variety?" They want me to say 90, 100, 110, 120 days, etc. I respond by saying, "I don't think like that" and they nearly always quip, "Well, we do". There seems to be some level of contempt, implying that I don't know maturities. But it is not that. My varieties are frequently in small plots and I judge the maturuty in several ways:
natural senescence,
relative to a standard market variety,
early, medium, or late,
bulking maturity with relevance to vine kill,
and finally...maturity based on skin set.

Sometimes my plots are within commericial fields in which everything is killed at one time, and I don't get to view the natural maturity of each of the clones. Sometimes I hand planted at various times. So I can't clearly say and/or think Day Maturity.

Maturities can be relegated meaningless if one messes with the timing of fertilities, waterings, day of planting, designations of fresh harvest/storage harvest, rapid shifts in the weather and on and on.

"What day maturity is it?", the grower will ask.

My eyes dart around thinking of all the nuances of factors.

."You don't know, do you?

My eyes stop dancing, looking straight ahead at the grower, in disbelief, thinking No, not again!

If I am lucky, I get to talk to this grower again some time in my life.

Gimme, back to vine kill. Organic growers with acreage. will mow, beat, or otherwise cut the vines down. This is followed a few days later by flame burners. This helps destroy any green left on the vine and controls weeds too. As the field dries down, the grower will wait one, two, three, four or more weeks before harvest when the skin finally sets. The grower will dig a hill or two and try to slip the skin on a potato or two determining maturity.

So, is maturity when you can dig, when you can kill, or natural maturity? You be the judge!

Conventional growers sometimes just beat the vines down. Some use chemical defoliants in the paraquat class. There are various scenarios that, frankly, I think are too boring for this forum.

asking you a potato question is like gettin good inside tips down at the horse track...when answered.

Funny you think my potato tips are worth much, especially since you think I must be down on the horse track. Well, I guess I grew up a cowboy of sorts. I remember one time my dad and I were out in the bull pen at the family farm.

My dad said, "Son, Why do you always walk and talk looking at your boots like that Schrader boy?"

I said, "Dad, Look at it this way. If I don't talk and walk looking down, I'll step in it too!"

Tom Wagner

[Gimme3]

Tom Wagner....look...Man...vent anytime you want to in a thread or question i posed. To me...you are a difficult person to compliment verbally...nothin i tell you...is absorbed in the manner sent, outside of Questions. Thats ok...cause that aint why we are here to start with anyhow.

In my life... i've learned the truth of the Statement "There's a lot of Ways to Skin a cat". You dun seen probly a Million cats skinned (potato growin)...so...Who better to ask when lookin for better ways...huh ? And you have the Scientific approach and answers, that a layman simply dont have.

I look for ways, new to my own thinkin...ways that thru the Grace of Life an God...someone else has a better understanding of. I never get tired of learnin. Or tryin somethin New.

Must be a great chasm...when a commercial grower queries a Life-long scientist in the wrong way. Vent at will...

My question regarding senescence is motivated simply by this...i double-crop. If theres a way i can speed up potato harvest so as to be able to prepare the rows for the next endeavor...im interested in learnin about it.

You dun answered very well...the things i was truly wonderin, Tom, an i genuinely Thank ya for that, an look forward to future conversations an Wit w/ya...)))

TY... 8)