# Lawn care calendar for Louisiana: when to fertilize and seed > Louisiana lawn calendar: St. Augustine and centipede from mid spring to early fall, potash not nitrogen in September, crabgrass preventer in February. Canonical: https://lucernel.com/guides/lawn-care-calendar/louisiana Last updated: 2026-10-28 Louisiana lawns are warm-season grasses, mostly St. Augustinegrass and centipedegrass, with bermudagrass and zoysiagrass for sun and wear. The LSU AgCenter sees a split between north and south that moves every job by two to four weeks, and a September feeding that swaps nitrogen for potash. **Feed Louisiana lawns through the growing season, then swap to potash in September.** The LSU AgCenter says centipedegrass and St. Augustinegrass grow actively from mid spring through early fall, so feeding runs across that window: three to four applications of 1 pound of nitrogen per 1,000 square feet for St. Augustine and half as much for centipede. In September it advises a low-nitrogen, high-potash fertilizer, and no fall feeding in October. Crabgrass preventer goes on in mid to late February in Baton Rouge and early March in Shreveport. (LSU AgCenter) | Month | Feeding, mowing and watering | Weeds, planting and other jobs | | --- | --- | --- | | January | Dormant; no feeding | Cool-season weeds are active; plan weed control for late winter | | February | Dormant; wait for growth | Crabgrass preventer mid to late February around Baton Rouge | | March | Growth begins; start the feeding plan once the lawn is growing (our suggestion) | Preventer in early March around Shreveport and Monroe | | April | Active growth from mid spring; 1 pound of nitrogen per 1,000 square feet, half that rate on centipede | Sod, sprigs or seed go down once soil reaches 70 F at 2 inches | | May | Feed to a total of three or four applications on St. Augustine; mow St. Augustine at 2.5 inches (3 in shade) | Centipede is mowed at 1 to 1.5 inches (1.5 in shade) | | June | Water deeply and infrequently, to about 4 inches of wet soil | Scout for chinch bugs and army worms | | July | Mid summer is the time to thicken the lawn; keep the one-third mowing rule | Leaf spots and take-all patch are the disease watch | | August | Last full-nitrogen feeding window | Check the weed plan for fall | | September | Low-nitrogen, high-potash fertilizer; raise the mower a notch except on centipede | Brown patch is the main fall disease on warm-season grass | | October | No fertilizer; clear fallen leaves; water if the fall is dry | Aerating and dethatching are not needed in fall | | November | Dormant | Fall weed control | | December | Dormant | Nothing to apply | LSU gives the rates and the September rule; the monthly spacing between April and August is our reading, because its calendar chart marks mowing and watering across the whole growing season rather than dated feedings. ## Which grasses grow where in Louisiana The LSU AgCenter calls centipedegrass and St. Augustinegrass the most common lawn grasses in the state. All warm-season grasses can grow here. St. Augustine has the coarsest texture and moderate to high upkeep, and some varieties struggle with chinch bugs and a decline virus. Centipede is medium-textured, needs less maintenance and a lot of water in dry spells, and can slide into decline syndrome if it is overfed. Bermudagrass wants full sun, high fertility and a reel mower if it is cut below 1 inch. Zoysia makes the best-looking lawns but grows slowly and builds thatch. LSU notes that severe cold in north Louisiana often injures or kills the less hardy grasses, among them St. Augustine and carpetgrass, and says low nitrogen and high potassium in late summer strengthens their cold tolerance. ## Frost dates from NOAA Dates are the NOAA 1991-2020 normals for the last spring and first fall 32 F freeze at 50% probability. At Shreveport the last spring frost averages March 9 and the first fall frost November 18. At Lafayette Regional Airport the dates are February 13 and December 4. At New Orleans (Audubon) they are January 24 and January 2, so in half of all years New Orleans does not freeze until after New Year. Counting the days between them, Shreveport has about 254 frost-free days and Lafayette about 294 (our arithmetic). LSU says north and south Louisiana differ by two to four weeks in when jobs start and end. Lafayette's average last freeze comes 24 days before Shreveport's and its first comes 16 days after (our arithmetic). ## Spring and early summer Crabgrass seed germinates when the soil warms to 55 to 60 F, which LSU places in mid to late February around Baton Rouge and early March around Shreveport and Monroe. That sets the preventer date. Healthy turf crowds out crabgrass, and the guidance stresses that thin lawns let light reach the seed. LSU says to plant warm-season sod, sprigs or seed when the soil warms to about 70 F at 2 inches deep, and to have the soil tested at least a month before planting. St. Augustine is planted as sod or plugs, since it is not grown from seed, while common centipede can be seeded on sandy soil that will not crust. ## Summer Mid summer is the time to grow and thicken the lawn. St. Augustine takes three to four applications of 1 pound of nitrogen per 1,000 square feet a season and centipede half as much, and LSU warns that missing this difference can lead to centipede decline syndrome. A general fertilizer with a 3-1-2 or 4-1-3 ratio fits the average soil; a 9-1-1 product works if you add potash in early fall. LSU says the old one inch a week rule means little, because clay holds up to two and a half times as much water as sand. Water when the first dry or off-color patches show, enough to wet about 4 inches, then check with a shovel. Mow St. Augustine at 2.5 inches in sun and 3 in shade, centipede at 1 to 1.5 inches, and sharpen the mower blade twice in a season. ## Fall In September the emphasis changes from growth to strength. LSU says to use a fertilizer with less nitrogen and more potash, or muriate of potash at 1 to 2 pounds per 1,000 square feet if you fed mostly nitrogen all summer, and to apply any fall feeding in September because it is not needed later. Northern-blend winterizers that are high in nitrogen are the ones to avoid. Keep fallen leaves off the turf, water if the season is dry, and raise the cutting height a notch except on centipede. You do not need to aerate or dethatch in fall. LSU puts weed control in the cooler fall, late winter and spring so it does not stress the lawn. ## Fertilizer rules The Louisiana Department of Agriculture and Forestry runs a fertilizer program that covers registration, labeling and tonnage reporting. I found no state rule that limits phosphorus in home lawn fertilizer. The practical limit is on the bag: LSU recommends a 3-1-2 or 4-1-3 ratio, which has little phosphorus, and a soil test every few years. The calendar needs one more input: the pounds of nitrogen in a bag. The lawn fertilizer calculator on this site converts the first number on the label into pounds of product for your lawn. ## Frequently asked questions ### When should I fertilize my St. Augustine lawn in Louisiana? LSU recommends three to four applications of 1 pound of nitrogen per 1,000 square feet through the growing season, which runs from mid spring to early fall. Change to a low-nitrogen, high-potash fertilizer in September and skip October. ### When do I put down crabgrass preventer in Louisiana? When soil temperatures reach 55 to 60 F: mid to late February in Baton Rouge and early March in Shreveport and Monroe, according to LSU. ### How much nitrogen does centipedegrass need? Half as much as St. Augustine. Overfeeding can lead to centipede decline syndrome, according to LSU. ### How tall should I mow a Louisiana lawn? St. Augustine at 2.5 inches in sun and 3 inches in shade, centipede at 1 to 1.5 inches (1.5 in shade). Never remove more than a third of the leaf at once. ### Can Lawnzo help me with a Louisiana lawn schedule? Lawnzo for iPhone plans mowing, watering, feeding and weeding for your grass and tests each job against the forecast. When it holds one back, it shows why, and the journal remembers what you put down. ## Sources (checked 2026-10-02) - [LSU AgCenter, Summer Lawn Care](https://www.lsuagcenter.com/topics/lawn_garden/home_gardening/lawn/summer-lawn-care) - [LSU AgCenter, Preemergence Options for Crabgrass Control in Louisiana Lawns](https://www.lsuagcenter.com/topics/lawn_garden/home_gardening/lawn/preemergence-options-for-crabgrass-control-in-louisiana-lawns) - [LSU AgCenter, Winterize Lawn With Potash, Not Nitrogen](https://www.lsuagcenter.com/topics/lawn_garden/home_gardening/lawn/winterize-lawn-with-potash-not-nitrogen) - [LSU AgCenter, Louisiana Lawns Fact Sheet: Turfgrass for Louisiana Lawns (pub. 2230)](https://www.lsuagcenter.com/topics/lawn_garden/home_gardening/lawn/cultural_information/louisiana-lawns-fact-sheet--turfgrass-for-louisiana-lawns) - [LSU AgCenter, Culture Calendar for Warm Season Grasses](https://www.lsuagcenter.com/topics/lawn_garden/home_gardening/lawn/cultural_information/culture-calandar-for-warm-season-grasses) - [Louisiana Department of Agriculture and Forestry, Fertilizer and agricultural lime](https://www.ldaf.la.gov/plants/fertilizer-lime) - [NOAA NCEI 1991-2020 normals: frost dates for New Orleans, Shreveport and Lafayette (API query)](https://www.ncei.noaa.gov/access/services/data/v1?dataset=normals-annualseasonal-1991-2020&stations=USW00012930,USW00013957,USW00013976&dataTypes=ANN-TMIN-PRBLST-T32FP50,ANN-TMIN-PRBFST-T32FP50&format=json) - [NOAA NCEI, U.S. Climate Normals 1991-2020 (product page)](https://www.ncei.noaa.gov/products/land-based-station/us-climate-normals)