How to tap a maple tree

Tap a day or two before the first good stretch of freeze-thaw weather: nights below freezing and days climbing to about 40°F. Don't go weeks early. Tapholes slowly dry up and heal over, usually within 6 to 10 weeks, so an early hole can quit before the late runs.

Start with trees on south-facing slopes, which warm up and run first. If you can, avoid drilling on a hard-frozen day, when the wood is more likely to split. Your state's typical dates are on the when-to-tap pages, and the sap forecast shows when the first freeze-thaw days are coming.

Measure around the trunk at chest height (4½ feet) and divide by 3.14 to get the diameter. Current conservative guidance from UVM's Proctor Center, the Producers Manual and UNH Extension starts tapping at 12 inches across, about 38 inches around. Older guides (UMaine, Cornell's beginner notebook) still say 10 inches.

Pick healthy trees with full crowns. Sugar and black maples are the best, but red maples and several other trees work too. See which trees you can tap, and how to tell them apart with the leaves off.

Fewer than you'd think. More taps don't mean proportionally more sap, and every hole costs the tree some clean wood. Sources genuinely disagree here; the research trend is conservative:

Cornell's maple program argues for even fewer: one tap per tree unless it's fast-growing or very large. Run your own trees through the taps-per-tree calculator.

1. 1

   Clean your gear

   Use a clean, sharp bit. Sanitize the bit and spouts in 1 ounce of household bleach per pint of water, then rinse.
2. 2

   Choose a fresh spot

   Stay at least 2 inches (better, 4) to the side of last year's holes and 6 inches above or below them, and at least 6 inches from wounds or branch scars. An old hole leaves stained wood that can run 12 to 18 inches above and below it.
3. 3

   Drill a 5/16-inch hole

   7/16 inch was the old bucket standard, but 5/16 (or 19/64) gives about the same sap and heals faster.
4. 4

   Go about 1.5 inches into the wood

   UVM's maximum is 1.5 inches, up to 2 on very vigorous trees. Never go more than 2 inches into the wood itself, and add the bark on top.
5. 5

   Angle it slightly up

   Tilt the drill so the back of the hole sits a little higher, about 10°, so sap drains out toward the spout.
6. 6

   Leave the hole alone

   Don't blow it out, and don't put bleach, alcohol or pellets in it. Sanitizer in the hole can shorten its life, and paraformaldehyde pellets are illegal in the US and Canada.
7. 7

   Tap the spout in gently

   Tap until the sound changes to a dull thud, then stop. Driving it harder can split the wood, especially when it's frozen or in red maple.

Hang a covered, food-grade bucket or bag on the spout, or run tubing. Skip old metal gear. Lead in sap concentrates 30 to 100 times in the syrup, and the maple industry's own guidance flags old tin or terneplate spiles, “tin” buckets, galvanized equipment made before 1994 and pans soldered with lead before 1995.

Pull spouts gently as soon as the season is over, and don't plug the holes. Leaving spouts in through the growing season slows healing; healthy trees close their tapholes in one to three years. Here's how to tell the season is over.