Frost Dates and Zone
- Madison is mostly in zone 5b on USDA's 2023 hardiness map: the coldest night averages -10 to -15°F.(UW–Madison Extension)
- Last spring frost: half of years see one after May 1, and there's only a 10% chance after May 16. Hold tender plants until mid-May.(NOAA 1991–2020 normals, Madison airport)
- First fall frost: October 10 in a typical year; by September 26 in 1 year in 10, and as late as October 24.(NOAA) The frost-free season runs about 160 days.(NOAA)
- The State Climatology Office says Madison's last spring freeze has moved about two weeks earlier since 1950, more than any other major Wisconsin station.(Wisconsin State Climatology Office)
Lawn Care Timing
- Feed around Labor Day. It's the most important feeding of the year, and for a low-maintenance lawn it can be the only one.(UW–Madison Extension) Each feeding should supply about 1 pound of nitrogen per 1,000 square feet; with a 20% nitrogen product, that's about 5 pounds of fertilizer.(UW–Madison Extension)
- Spring feeding: wait until May, after you've mowed twice.(UW–Madison Extension) Feeding in early to mid-October can push tender growth into winter and invite snow mold; if in doubt, wait for spring.(UW–Madison Extension)
- Seed from late August to early September, finishing by about September 10 to 15.(UW–Madison Extension)
- Aerate any time in October when the soil is moist.(UW–Madison Extension)(UW–Madison Extension) Thatch is only a problem over about half an inch, and UW prefers core aeration to power dethatching, which tears up the lawn.(UW–Madison Extension)
- Mow at 3 inches or higher, higher in summer, and never take off more than a third of the blade.(UW–Madison Extension)(UW–Madison Extension) Keep the same height for the last mow of the year.(UW–Madison CALS)
- Water about an inch a week, deeply and not often, or let the lawn go dormant in a drought. Once it's brown, don't try to green it up; in a long drought, a little water every two weeks keeps it alive.(UW–Madison Extension)
- Crabgrass sprouts once the soil is near 60°F for several days, so a preventer by early May works in southern Wisconsin. Skip it where you'll seed; most products stop grass seed too.(UW–Madison Extension)
- Grubs: most Wisconsin lawns don't need treatment. If you've had grub damage, preventive products go down around beetle egg-laying in late spring and summer.(UW–Madison Extension)
The Phosphorus Law
Wisconsin limits phosphorus lawn fertilizer to protect lakes, and the law covers homeowners too.(DATCP)
- If the middle number on the bag isn't zero, you can use it only when starting a new lawn from seed or sod, or when a lab soil test under 36 months old shows a phosphorus shortage.(DATCP)
- No fertilizer of any kind on frozen ground. DATCP's test: if you can't dig down 6 to 8 inches, it's frozen.(DATCP)
- No fertilizer on driveways or sidewalks. Sweep spills back onto the lawn; never wash them into a storm drain.(DATCP)
- Fines run up to $50 the first time and $200 to $500 after that.(DATCP)
Weeds
Creeping Charlie
Round, scalloped leaves, square stems and a minty smell when crushed. It likes shade and wet spots. The most effective weed killers contain triclopyr or sulfentrazone, applied in mid to late fall after the first frost. Borax doesn't work well and can hurt the lawn.(UW–Madison Extension)
Dandelions and Clover
Dandelions and white clover feed pollinators, and lawns mowed above 3 inches and less often have more of them.(UW–Madison Extension) If you'd rather treat dandelions, fall is the best time.(UW–Madison Extension)
Poison Ivy
Three leaflets, the middle one on its own short stalk; a low shrub or a climbing vine, with whitish berries in late summer. Every part carries the oil that causes the rash, and it stays active on dead plants for years. Wear long sleeves, long pants, boots and gloves. Never burn or compost it; bag it for the trash. Sprays work only when the leaves are fully out, summer to early fall; cutting the stem and painting the stump works any time.(UW–Madison Extension)
Invasive Plants
Under Wisconsin's invasive species rule, you can't move or spread "restricted" plants. Controlling them on your land is encouraged, not required.(Wisconsin DNR)
- Wild parsnip: tall stalks with flat clusters of small yellow flowers. Its sap plus sunlight burns skin, so cover up. Cut the root 1 to 2 inches below the soil, and bag flower heads for the landfill.(Wisconsin DNR) DNR also mentions burning them, but burning is banned in Madison.(Madison Fire Department)
- Garlic mustard: smells like garlic, with small white four-petal flowers in spring. Pull it in early spring before it seeds, getting the root, and bag flowering plants for the trash. Seeds last at least seven years, so expect to keep at it.(Wisconsin DNR)
- Buckthorn: a shrub or small tree that stays green after other plants drop their leaves, with orange inner bark and black berries. Pull small ones; cut big ones and treat the stump in late fall or winter.(Wisconsin DNR)
- Japanese knotweed: hollow, bamboo-like stems and cream flower plumes in August and September. Pieces as small as a couple of inches can regrow, so dispose of it carefully.(Wisconsin DNR)
- Jumping worms: thrash like snakes and leave soil that looks like coffee grounds, most noticeable in late summer and early fall. They spread in mulch, compost and potted plants; buy compost and mulch that's been heated, and bag any worms you find for the trash.(Wisconsin DNR)
DNR has native plant guides, plant lists and a list of native plant sales on its native plants page.(Wisconsin DNR)
Trees
- Oaks: oak wilt is in Dane County.(Wisconsin DNR) DNR says the highest risk of spreading it is April through July and winter is the best time to prune; seal any wound made then right away.(Wisconsin DNR) In Madison, any work on an oak, even on private property, needs a free city permit from April 1 to October 15.(City of Madison)
- Elms: don't prune native elms from May through November, because of Dutch elm disease.(Wisconsin DNR)
- Ash: emerald ash borer was first found in Madison in 2013(City of Madison) and is in every Wisconsin county as of 2024. Weigh the tree's value against the cost: most treatments are yearly, and removal is always an option.(UW–Madison Extension)(UW–Madison)
- Other trees: dormant pruning can start in February once the weather eases. Skip wound dressing on routine cuts.(UW–Madison Extension)
- Terrace trees in Madison are the city's: Urban Forestry prunes, removes and replants them at no extra charge.(City of Madison) Don't trim them yourself; request work at 608-266-4816.(City of Madison)
Leaves and the Lakes
- Leaves carry phosphorus. Rain on leaf piles in the street makes a "leaf tea" that runs down storm drains and feeds algae in the lakes, so keep leaves out of the street, by ordinance and before rain especially.(City of Madison)
- Madison's advice: if leaves cover about a fifth of the lawn, leave them; at about half, mow them in or use them as mulch in beds.(City of Madison) Mowing them in has been shown to cut weeds the next spring.(UW–Madison CALS)
- For pickup, pile leaves on the terrace. Fall 2026 collection started October 4, with three set-outs per neighborhood.(City of Madison) Pickup days and drop-off sites are in the trash and pickup guide.
Madison Yard Rules
- Keep grass and weeds under 8 inches.(City of Madison) In 2025 the city paused enforcement for Low Mow May and suggested mowing every 14 days at 4 to 5 inches; no 2026 announcement was found.(City of Madison)
- No burning of leaves, brush or yard waste. A backyard fire pit is limited to clean, dry wood, 15 feet or more from buildings and lot lines.(Madison Fire Department)
- Free mulch: residents can take up to 30 gallons at the Quann-Olin Parkway drop-off site, when it's stocked.(City of Madison) Drop-off sites take yard waste and brush through December 3, 2026, then switch to winter hours.(City of Madison)
Rain Gardens
- Madison's terrace rain garden program costs the owner $100, added to the tax bill, and includes the native plants and planting. The terrace must be at least 10 feet wide, with no gas or water main under it.(City of Madison)
- For a rain garden on your own lot, the city reimburses part of the cost, figured with its calculator. Get approval by email before you buy anything.(City of Madison)
Full Calendar
January
- Plan, don't feed: no fertilizer on frozen lawns. State law bans fertilizer on frozen turf (can't dig 6-8 in.).(source)
February
- Start dormant pruning of most trees and shrubs. UW: dormant pruning can begin once February arrives and weather moderates.(source)
- In Madison, schedule any oak work before April 1. Oak wilt risk; Madison requires a permit for oak work Apr 1-Oct 15.(source)
March
- Finish oak pruning; avoid oaks April through July. DNR: highest oak wilt risk April-July; winter is best.(source)
- Cut and treat buckthorn stumps before leaf-out if not done in fall. DNR lists triclopyr cut-stump/basal bark late fall through winter.(source)
April
- Pull garlic mustard while it's small, before it sets seed. DNR: hand-pull in early spring before seed set; bag for trash.(source)
- Treat valuable ash trees for emerald ash borer (hire an arborist). EAB is in every Wisconsin county as of 2024.(source)
- Don't prune elms from May on. DNR: avoid pruning native elms May through November.(source)
May
- Apply crabgrass preventer by early May (not where you'll seed). UW: crabgrass germinates near 60 F soil; early May not too late in the south.(source)
- Fertilize after you've mowed twice (about 1 lb N/1,000 sq ft). UW: May is the target month for spring feeding.(source)
- Plant frost-tender plants after mid-May. NOAA: 10% chance of a 32 F frost after May 16 in Madison.(source)
- Try Low Mow May: mow every 14 days at 4-5 inches. Madison suspended tall-grass enforcement in May 2025.(source)
- Spot-treat or dig wild parsnip before it flowers; wear gloves and sleeves. DNR: sap plus sunlight burns skin; mature-plant herbicide mid-May to mid-June.(source)
June
- Raise mowing height to 3 inches or more. UW: 3 inches is the minimum; go higher in summer.(source)
- Cut wild parsnip roots or flower heads before seed set. DNR: cut root 1-2 in. below soil; landfill flower heads.(source)
- Only if you have a grub history: apply preventive grub control. UW: most lawns don't need it; time it to beetle egg-laying.(source)
July
- Water 1 inch a week, or let the lawn go dormant. UW: dormant lawns survive; water a little every 2 weeks in long drought.(source)
- Spray poison ivy now while leaves are fully out. UW: foliar sprays work in summer and early fall.(source)
August
- Seed or overseed bare spots from late August. UW: seed late Aug to early Sept, up to about Sept 10-15.(source)
- Watch soil and mulch for jumping worms. DNR: most noticeable late summer and early fall.(source)
September
- Fertilize around Labor Day (1 lb N/1,000 sq ft). UW: Labor Day is the optimum feeding time in Wisconsin.(source)
- Finish seeding by mid-September. UW cutoff is about Sept 10-15.(source)
- Use no phosphorus unless seeding or a soil test says so. Wis. Stat. 94.643 phosphorus rule.(source)
October
- Core aerate when soil is moist. UW: all of October is suitable.(source)
- Treat creeping Charlie and dandelions if you choose to. UW: fall is optimum for broadleaf weed control.(source)
- Mow leaves into the lawn; keep them out of the street. Leaves in streets send phosphorus to the lakes.(source)
- Expect the first frost around Oct. 10. NOAA median first 32 F in Madison: Oct 10.(source)
November
- Rake curb leaves before rain; set piles on the terrace for pickup. Madison: never place leaves in the street.(source)
- Cut buckthorn and treat stumps (it stays green when natives drop leaves). DNR: glyphosate cut-stump in late fall.(source)
- Make the last mow at your normal height. UW turf: don't mow it really short.(source)
December
- Prune elms and other trees only once dormant; no fertilizer on frozen ground. DNR elm window ends Nov; state frozen-ground rule.(source)
Questions
When is the last frost in Madison?
Half of years see a last spring frost after May 1, based on NOAA's 1991–2020 averages for the Madison airport. There's only a 10% chance of frost after May 16, so mid-May is the safe time for tomatoes and other tender plants. The first fall frost averages October 10.
What growing zone is Madison, Wisconsin?
Mostly zone 5b on USDA's 2023 hardiness map, meaning the coldest night of the year averages -10 to -15°F. Some parts of the area are still 5a.
When should I fertilize my lawn in Wisconsin?
Around Labor Day is the most important feeding, and for a low-maintenance lawn it can be the only one. If you feed in spring, wait until May, after you've mowed twice. UW Extension suggests about 1 pound of nitrogen per 1,000 square feet each time.
When should I plant grass seed in Madison?
Late August to early September, finishing by about September 10 to 15. Don't use crabgrass preventer where you plan to seed; most products stop grass seed too.
Can I prune my oak tree in summer in Madison?
Not without a permit. Madison requires a free permit for work on any oak, including on private property, from April 1 to October 15, because of oak wilt. Statewide, DNR says the highest risk is April through July and winter is the best time to prune.
Can I burn leaves in Madison?
No. Madison bans open burning of leaves, brush and yard waste. Mow leaves into the lawn, use them as mulch, or rake them onto the terrace (never the street) for city pickup.
How tall can my grass be in Madison?
Under 8 inches. In May 2025 the city paused tall-grass enforcement for Low Mow May; no 2026 announcement was found.