When is the Best Time for Sugarmakers to Tap their Maple Trees?

When is the Best Time for Sugarmakers to Tap their Maple Trees?

Sugarmakers begin drilling holes and hammering spouts into their maple trees at their own discretion, and each has particular schedules and reasons for tapping when they do. Still, the traditional time for tapping has always been right around the first of March, at least in northern New England. But this is changing. Just as we’ve seen long-standing sugaring traditions like buckets and horses give way to newer conventions like plastic tubing and vacuum systems, we’ve also begun to see changes in the traditional sugaring tapping schedule.

Sugaring operations come in all kinds and sizes – from a few reused milk jugs the kids hang on driveway maples to imposing, sophisticated operations with tens of thousands of taps. Regardless of scale, though, all sugarmakers want to be tapped and ready in time to catch the best sap runs. Nobody wants to tap too late and miss out on a gusher. And yet many do. When Tim Wilmot, the University of Vermont Extension Maple Specialist, asks sugarmakers at the end of each year about what they wish they’d done differently, by far the most common response is that they wished they had tapped earlier.

Why did they wait? Because tapping too early has always been regarded as dangerous. The traditional fear is that early tapped holes might “dry out” and give less sap when good sugaring weather arrives many weeks later. And so many sugarmakers agonize over the when-to-tap question during every warm spell in early February.

For large-scale sugarmakers with many tens of thousands of taps, however, there’s not much choice. It takes them weeks or even months to be fully tapped and ready; they can’t afford to wait until March. Thus many of them break with tradition, tapping as early as mid-January.

This all begs some important questions: Do early season tapholes actually dry out earlier than March-drilled ones? And what tapping start date gives a sugarmaker the greatest sap volume for a season?

Tim Wilmot designed experiments to address those fundamental questions. At UVM’s Proctor Maple Research Center in Underhill, Vermont, Wilmot divided maple trees into three groups according to when they were tapped – early, traditional, late – and then compared the volume of sap collected from each category over several years. He did so using both gravity and vacuum-based collecting systems, both being commonly used by sugarmakers.

The tapholes in Wilmot’s earliest group were a month older than those in his traditional group, yet at the end of the year, sap yields were very similar. “We have learned that you can tap in January and it doesn’t diminish your eventual sap yield,” said Wilmot. “The experiments showed that while tapping early did not appear to hurt overall sap yields, neither did it supplement them.”

As to “drying out,” Wilmot explains that the term is not entirely accurate. What happens is that a great variety of fungi, bacteria, and yeasts live in maple forests and they flourish as temperatures rise. Such microbes inevitably infect the tapholes, interacting with the sap inside to form a gummy substance that blocks further sap flow. They don’t really dry out, but they do give less sap when infected.

Wilmot explained that microbial infection is a late season problem: “January and February thaws may allow sap flow but rarely involve the prolonged warmth seen in April.” Accordingly, microorganisms don’t cause as much blockage in the colder, early season but are a significant factor toward the end of the season. As Wilmot reported, “Under both gravity and vacuum, sap flow from tapholes drilled in January and February was comparable to sap flow from much fresher holes during the cooler part of the sap flow season.” But, he cautioned, “Toward the end of the season, when temperatures had exceeded 50oF on several days, January and February tapholes yielded less sap than newer ones.”

Wilmot interprets all this to mean that there can be benefits to getting out in the sugar woods and tapping early because those late season reductions in flow from older tapholes may be compensated for by capture of early-season flows. “In years when many of the sap flow periods involve relatively low temperatures, perhaps 40oF or less, the additional yield from early tapping may provide a significant advantage compared to tapping on March 1.”

Michael Snyder is a forester in Stowe, Vermont

  1. David Menard
    Jan 12, 2014

    Just want to get an inside help on when to tap trees here in Worcester, MA. I read the article above and it was a great help.

  2. Doug
    Mar 10, 2014

    Just wondering;  Our frost level is down up to nine feet in places.  Any ideas how this will affect the tapping timing?  I have never seen the frost down so deep.(I have been tapping for 30 years) Makes me wonder if this will affect my timing.  If anyone responds, please send a copy to my email address.. DLV

  3. Billy
    Nov 03, 2015

    Your articles are a great help, thank you

  4. Robert
    Jan 28, 2016

    Doug, I haven’t been sugaring for 30 years, but correct me if I’m wrong…the sap we collect comes from the crown of the tree not the root system. As the sun warms the tree gravity or suction pulls the sap from the crown. I don’t believe frost 9 feet deep will effect yield.

  5. Patrick
    Jan 30, 2016

    As one who has tapped tress for forty years, I have never seen the likes of this year.  Wells around the trees prompted me to tap January 30, 2016 and sap is flowing. Thank you for your information.  I found it very useful.

  6. Collin
    Mar 24, 2016

    Robert, the sap comes from the roots. It gets collected by the leaves and stored in the roots for the winter. Releases the sugars and amino acids in the spring which is sap.

  7. Dave
    Mar 24, 2016

    I think Robert and Collin are both part right. Here’s a column written by Tim Wilmot of the Proctor Maple Research center which explains the sap flow mechanics of a tree fairly well. If after reading it you pretty much understand what’s going on, then you’re doing better than most. http://www.uvm.edu/~pmrc/wilmot_underpressure.pdf

  8. John hasting
    Jan 22, 2017

    Thank you for all of the research that you have done and the willingness to pass it on, to all, John

  9. Angela sisneros
    Sep 13, 2017


    I never tapped a maple tree before to make syrup and I am interested in learning this process. What would be the best time to tap trees in Maryland? Once I learn this process, I would like to take some low income kids in my neighborhood and show them how it’s done. Also can you boil it on top of your stove down to the syrup that you want? What is an efficient way for me to be able to do it out of my kitchen?

    Thank You,
    Angela Sisneros

  10. Phil Bemis
    Jan 24, 2018

    I have tapped in Jan, Feb, March doesn’t seem to make much difference.

  11. Peter
    Feb 18, 2018

    From my understanding the warn daytime causes the sap (sugar water) to flow down.  Pressure builds in the tree above ground as the tree warms up.  Night time the tree cools down and creates a negative pressure (vacuum) and draws water up the tree.

  12. Brian Weeks
    Dec 14, 2018

    We have been tapping earlier every year and last year (2018) we tapped the first week of January and the sap was already flowing as we had 3 January thaws. The sap flow started and stopped all season and we were done by the first week in April. The Walnut trees we also tap never produce the sap that the Sugar Maples do.

  13. Al Ulrich
    Jan 21, 2019

    Thanks for this helpful article summary. I was trying to figure this out, myself. Do you think the species of maple you’re tapping should factor into whether to start sooner or later?

  14. Dave Mance
    Jan 29, 2019

    Nope. All the maples should run at roughly the same time.

  15. Gordie Fuller
    Feb 17, 2019

    Great info, I really wanted to know about tapping early, because I actually already collected over 60 gallons of sap when we had the January thaw just this year 2019.

    I have been torn about pulling all the taps because the sap ran strong for a week and then it has been cold ever since.  I have not pulled my taps, I guess I will see what happens when it starts again.

  16. Shawn
    Mar 06, 2019

    Very interesting. I’ve been waiting to tap till just as the flow starts. I’m going to tap now after reading the above article. -25C and 40 inches of snow here yet.

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