2019 Maple Sap Summary

When is the best time to tap a maple tree in Southeastern Pennsylvania?

That was my number one question when I first decided to get started in this hobby. When do you put the tap in the tree?

Unfortunately, when I searched around, all I found about the topic was general advice.

General advice

Most of the advice I found stated that the ideal time to tap a maple tree is when the sap is flowing…

Sap flows when the nighttime temperatures dip below freezing, and the daytime temperatures get into the 40s.

This process of freezing and thawing causes water pressure in the tree that produces the sap flow we want.

Once the temperature gets too warm (if it doesn’t get below freezing at night), the sap flow stops, ending the season.

Well, that helped…a little…but it still didn’t answer my question. I found out there are also a few other considerations as well.

Other considerations

It depends on what type of trees you have, certain types of maple trees will produce buds sooner than others.

Once the buds emerge from the branches, it turns the flavor of the sap.

I found out that taps dry out about ~8-10 weeks after starting them.

When did I tap my trees?

I have 2 silver maple trees at my house, not sugar maples (which bud and end the season a bit earlier than sugar maples). My gut also told me that once April rolls around in the Philadelphia metro area, the nights don’t dip into the 20s all that often, so I decided to go as early as I could.

The first weather report that looked like it would give me a few days was the week of January 19-25–so I tapped my trees on January 19, 2019.

Was it the best time to tap a maple tree in Southeastern PA? Answering that question is what the purpose of the rest of this article is about.

The only way to determine when the best time to tap was, to take good notes and look back over the season. Here is my account of the season.

Week 1: January 19-25

This adventure started on January 19th. I had cabin fever, some extra free time on the weekend, and the weather forecast warmed up.

See for yourself:

From the looks of it, I thought there would be 3 good maple sap days: Sunday, Wednesday, Thursday.

Here is how that sap collection really turned out. The tables in this report show how many ounces of sap were collected each week. I did not typically measure the ounces directly, I generally estimated.

Jan 19Jan 20Jan 21Jan 22Jan 23Jan 24Jan 25
Ounces of sap0018000104
Weekly total122
Season total122

As you can tell from the report, however, the sap wasn’t really flowing that well yet, although it did yield just under 1 gallon of sap for the week.

Week 2 January 26 – Feb 1

This week started out warm and then got bitterly cold towards the end of the week. In the news, they called it a polar vortex–a front of cold air that shot down from the North Pole.

It actually got even colder than this report shows–the temperature was below zero for a couple of the days. Here is what the sap collecting looked like:

Jan 26Jan 27Jan 28Jan 29Jan 30Jan 31Feb 1
Ounces of sap00096000
Weekly total96
Season total218

Weather conditions only held up for 1 collection day.

Week 3 Feb 2 – 8

At first glance, this weather looked P-E-R-F-E-C-T for collecting maple sap–and it was certainly pretty good.

As an important side note, too, since the weather looked like it was going to be perfect, I drilled a second hole in my very large maple tree. My thought process here is that it should help extend my season by about 2 weeks and double my production over many of the weeks in the middle.

Here is what that all translated into, in terms of sap collecting:

Feb 2Feb 3Feb 4Feb 5Feb 6Feb 7Feb 8
Ounces of sap038435280648064
Weekly total1024
Season total1364

The only day that was not productive was Saturday.

It looked like a good day, on paper, but it came off the bitterly-cold polar vortex temperatures and there just weren’t enough warm hours to thaw the ice.

But still, over 1000 ounces of sap in the week. This was an amazing amount of sap and certainly was a week I would not have wanted to miss.

Week 4 Saturday, Feb 9-15

The weather for this week looked too cold for the first half, but excellent for the second half.

Check out the sap collection for this week:

Feb 9Feb 10Feb 11Feb 12Feb 13Feb 14Feb 15
Ounces of sap00640363264250.8
Weekly total941.8
Season total2305.8

Saturday, Feb 9, Sunday, Feb 10 and Tuesday, Feb 12, turned out to be too cold to collect any appreciable sap.

While the temperature technically got above freezing each day, it didn’t stay above freezing long enough for the sap to run appreciably

Monday was an okay day, not great. I recorded 64 ounces of sap, but in truth, that is a bit low, because much of the sap was frozen solid when I collected it.

Since the pure water freezes first, it actually concentrates the sugar and other dissolved nutrients in the remaining sap. So while the volume was low (~64 ounces), the sugar content was higher than usual.

Wednesday, Thursday and Friday turned out to be very good days, with approximately 2- 3 gallons collected each night.

Week 5 Saturday, Feb 16 -22

Week 5 looked like a bumper week, from the beginning. The forecast had lots of nights below freezing and days in or very close to the 40s. This  is how it turned out:

Feb 16Feb 17Feb 18Feb 19Feb 20Feb 21Feb 22
Ounces of sap080308990363250.8
Weekly total1100
Season total3406

The pattern was still sporadic, with 3 really good days and two small days. Surprisingly, there wasn’t much to show for Saturday.

Not exactly sure why. It technically wasn’t a zero, but there was so little in the buckets that I didn’t bother to collect it, I just waited until Sunday and collected that small amount then.

Turned out that Monday and Thursday were the big days I had hoped (but not the biggest of the year), and Friday wasn’t too shabby either.

Wednesday started frozen and ended frozen, so I didn’t even bother.

All in all, however, Week 5 was the highest producing week so far, bringing in approximately 1100 ounces, or just about 8.33 gallons of sap for the week, and nearly 26 gallons for the season.

Week 6: February 23- Mar 1

Here is the weather looked like for week 6:

On the surface, the ranges look relatively suited to collecting sap, but the reality of the hourly weather, the temperature changes just didn’t hit the right pattern for the sap pressure to build up and release.

Here is what the week produced:

Feb 23Feb 24Feb 25Feb 26Feb 27Feb 28Mar 1
Ounces of sap0128128
Weekly total256
Season total3620

Week 7: March 2-8

Week 7 here looked pretty bad. A cold snap flattened out my weather and kept it below or too close to freezing for most of the week. The vast majority of sap was harvested on Sunday, March 2nd, which was the largest harvest of the year. Monday was decent, but then I got skunked for 4 days in a row after that.

Mar 2Mar 3Mar 4Mar 5Mar 6Mar 7Mar 8
Ounces of sap41616096
Weekly total672
Season total4292

Friday wasn’t a perfect day, but it did yield some sap.

Week 8: March 9 – 15

Watching the weather here is fascinating. It might sound repetitive at this point, but what is needed to produce large amounts of sap is a strong temperature differential dipping below freezing (by enough to form ice crystals in the tree–probably like the 20s) and then thawing out into the 40s. Last week, it was cold and didn’t get warm enough. This week’s weather produced a few days that seemed to be a textbook day in terms of temperature differential and a few that were actually too warm…UGH.

Mar 9Mar 10Mar 11Mar 12Mar 13Mar 14Mar 15
Ounces of sap0140.819280140.8
Weekly total554
Season total4845

and the actual sap yield appeared to be declining.

Week 9: March 16-22

At the start of this week, the weather (on paper) looked picture-perfect, but it turned out NOT to be that way. The temperature stayed above freezing for most of the week.

Monday looked like it was going to be textbook perfect, but it yielded no sap.

Take a look:

I checked Tuesday, and Wednesday, Thursday, Saturday. The lines were dry. No sap flowing. My season is over.

No sap flowed at all.

Taps were dry, on textbook perfect days (temperature wise).

Mar 16Mar 17Mar 18Mar 19Mar 20Mar 21Mar 22
Ounces of sap0000000
Weekly total0
Season total4845

Buds were on the branches. Not sure if this had something to do with it, too:

The season is over, for me. I pulled the taps on Sunday, March 23.

Week 10: March 23 -29

Here was the weather for the following week:

Monday-Wednesday might have been sap-producing days, based on the temperature differentials from morning until afternoon if the holes hadn’t dried up.

The rest of the week was definitely too warm.

Week 11: March 30- Apr 6

Here was the weather for the following week:

Even though it says the temperature is going down to 27 degrees on Monday, the hourly forecast showed it just barely creeping down below freezing. On paper, this week would have produced ZERO sap, unless Sunday-Monday truly did dip below freezing.


I tapped my trees on January 19 and then added 1 more tap to the largest tree on February 2. During the entire season, it is estimated that my two trees produced nearly 38 gallons of sap!!

Summary of sap collection in 2019 season by week in Southeaster PA

You can see that my taps yield sap for a total of 8 weeks (maybe it was ~6 weeks, recognizing that I started a second tap 2-weeks in).

So, when was the best time to tap a silver maple tree in Southeastern Pennsylvania in 2019?

From the looks of it, February 2nd, 2019. My season ran from the week of 1/19 to 3/9, but those first two weeks of the season were cold and yielded a little, whereas the March weeks had much better temperatures.

Looking back in hindsight, I wonder if one of the two taps in the larger tree had started to dry up in those first two weeks of March (after 6 weeks of producing), which is why the yields went down, even though the weather was decent.

So, all-in-all, I feel pretty good about when I started the season. 1/19 was a bit early, but it was pretty close. If I had a crystal ball and could start over again, starting 2 weeks later (2/2) may have extended the harvest a bit–but I’m not sure. Since I’d only be risking ~200 ounces of sap from those first 2 weeks, it’s worth the risk.

I certainly didn’t miss the season too badly, however, because the season was certainly over, temperature wise, by mid-week 3/23.


Deciding when the best time to tap a maple tree is really just a guess. It’s highly dependent on the weather. In 2019, I tapped my trees on 1/19 and got 38 gallons of sap! I think I could have improved that harvest a bit (maybe by another ~2-4 gallons MAX–and that’s being optimistic) if i started 2 weeks later. I have no way of knowing, it’s just a guess. If I had to pick a single, best date to start, I would say it was probably February 2nd, 2019, this year.

I hope that helps. Did you tap maple trees this year? If so, where do you live and when did you start? Any advice you would share here?

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