Lawn Care & Soil Temperature Guides | Soil Temps

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Growing Degree Days for Lawn Care: What GDD Is and How to Use It

Growing degree days (GDD) count the heat your lawn has banked over the season. Learn the base 50°F, simple-average model this site uses, why the base temperature and start date must travel with every number, and how turf managers use accumulated GDD to time crabgrass pre-emergent, annual bluegrass seedhead suppression, plant growth regulator reapplication, and grub control. Sourced from USA-NPN, Michigan State, Purdue, Cornell, and Iowa State.

Fall Armyworm in Lawns: Identification, Damage, and Response

Fall armyworms can strip a lawn to brown stems in 48 hours. This guide covers identification (the inverted Y head marking), the soap flush scouting test, damage patterns that move like a front, treatment thresholds and products, and which lawns recover on their own. Watch begins when 2-inch soil temperatures hold above 70°F in late summer. Sourced from university turfgrass extension research.

Fall Broadleaf Weed Control: The Best Kill Window of the Year

Fall is when broadleaf herbicide works hardest. Dandelion, clover, ground ivy, and plantain move carbohydrates to their roots in fall, and systemic herbicide rides along for a root-deep kill that spring applications rarely match. This guide covers the fall window by temperature, product picks for cool-season and warm-season lawns, the overseeding wait rule, and winter annual seedlings. Sourced from university turfgrass extension research.

First Frost, Ground Freeze, and Frost Depth: Reading Winter Soil

First frost, ground freeze, and frost depth are three different events on three different schedules. This guide explains how air frost relates to soil temperature, how deep the ground actually freezes by region, what frost depth means for lawns, irrigation, and digging, and how to track the freeze-up at your nearest soil station. Built on NOAA frost normals and live USDA station data.

When to Plant Garlic and Fall Bulbs by Soil Temperature

Plant garlic and spring bulbs when soil temperatures fall to about 60°F and keep declining, with roughly 50°F at planting depth the sweet spot for garlic. This guide covers the soil trigger, why the frost-to-freeze gap is the planting window, regional timing from the North to the Gulf South, planting depth, and what happens if you plant too early or too late.

When to Apply Winterizer: Late-Fall Nitrogen Timing by Soil Temperature

Apply winterizer when your 2-inch soil temperature falls through 50°F, typically late October to mid-November for cool-season lawns. This guide covers the late-fall nitrogen window, regional timing, why warm-season lawns skip it, and product selection. Sourced from university turfgrass extension research.

Fall Pre-Emergent Timing: Stop Poa Annua When Soil Falls Through 70°F

When to apply pre-emergent in fall: when 2-inch soil temperatures fall back through 70°F and keep declining. This guide covers poa annua and winter annual weeds, the falling-soil trigger, regional windows from the Upper Midwest to the Gulf Coast, the overseeding conflict, split applications for the South, and product picks. Sourced from university turfgrass extension research.

When to Aerate Your Lawn by Grass Type and Soil Temperature

Core aeration relieves compaction, but timing decides whether the lawn recovers in a week or struggles for a month. Learn the soil-temperature windows for cool-season and warm-season grass, why hollow tines beat spikes, how often to aerate by soil type, and how to pair aeration with overseeding and fertilizer. Step-by-step guide sourced from 15+ university turfgrass extensions.

Cool-Season Fertilization Schedule: A Soil-Temperature Nitrogen Plan

Stop guessing when to feed Kentucky bluegrass, tall fescue, perennial rye, and fine fescue. This guide builds a fall-heavy nitrogen schedule around soil temperature instead of the calendar: light spring feeding, no summer nitrogen, the year's heaviest feeding in early fall, and a soil-temp-triggered late-fall application. Step-by-step guide sourced from 15+ university turfgrass extensions.

Fall Overseeding Cool-Season Lawns: The 50-65°F Window

Fall is the best time of year to overseed tall fescue, Kentucky bluegrass, and perennial ryegrass. This guide covers the 50-65°F soil window, aeration prep, species seed rates, high-phosphorus starter fertilizer, the week-by-week watering cascade, and first-mow timing. Step-by-step guide sourced from 15+ university turfgrass extensions.

Winter Overseeding Warm-Season Lawns with Ryegrass: The 65-70°F Window

Bermuda and zoysia go tan in winter. Overseed with ryegrass to keep a green lawn through dormancy. This guide covers the soil-temperature trigger (65-70°F and falling), seeding rates, scalping, quick-release nitrogen, and the spring transition back to warm-season grass. Step-by-step guide sourced from 15+ university turfgrass extensions.

When to Apply Grub Control: The 65-70°F Soil Window

Apply preventive grub control (chlorantraniliprole or imidacloprid) before eggs hatch, when 2-4 inch soil holds 65-70°F: late June through July in most regions. Save curative trichlorfon for August-September, water in 0.5 inch after applying, and only treat when counts pass 8-10 grubs per square foot. Sourced from 15+ university turfgrass extensions.

Lawn Irrigation Timing by Soil Temperature

Stop watering by the calendar. This guide ties irrigation depth and frequency to soil temperature, explains the deep-and-infrequent rule that builds drought-proof roots, shows how to audit your sprinklers with catch cups, and adjusts the schedule for clay versus sandy soil. Step-by-step guide sourced from 15+ university turfgrass extensions.

Lawn Fungus by Temperature: Brown Patch, Dollar Spot & More

Brown patch and Pythium strike when humid nights hold above 68°F on lush, over-fertilized turf; dollar spot, red thread, and rust hit slow-growing lawns at 60-85°F. The temperature window for each disease, the 4-8 AM watering rule that prevents most of them, and how to rotate FRAC codes when a fungicide is warranted. Sourced from 15+ university turfgrass extensions.

Pre-Emergent vs Post-Emergent: When to Switch

Your pre-emergent window closes the day crabgrass germinates, and most homeowners miss it by weeks. This guide pins the exact soil-temperature switch point, the four rescue scenarios when you are late, and the split-application strategy that makes timing mistakes survivable. Step-by-step guide sourced from 15+ university turfgrass extensions.

Grass Seed Germination Soil Temperature by Species

The soil temperature each grass species needs to germinate, from 15+ university extensions: tall fescue and perennial ryegrass 68-86°F, Kentucky bluegrass 59-86°F, fine fescue 59-77°F, cool-season 50°F trigger, warm-season 65°F. Per-species germination bands and days, seeding depth, moisture, and viability testing so your seed sprouts the first time.

How to Read a Soil Thermometer for Lawn Timing

A warm afternoon does not mean warm soil, and the wrong depth or a single reading sends you applying products too early or too late. This guide shows you exactly how to read soil temperature: dial vs digital, 2-inch vs 4-inch depth, where to probe, when to probe, and how to track a trend. Step-by-step guide sourced from 15+ university turfgrass extensions.

Summer Lawn Dormancy: Keep Cool-Season Grass Alive in Heat

Cool-season grass slows once 2-inch soil sustains 75°F and goes dormant near 85°F. Dormant is not dead: raise mowing to 3-3.5 inches, water 1-1.5 inches per week deep and infrequent, and cut off nitrogen until fall. How to tell dormant grass from dead, sourced from 15+ university turfgrass extensions.

Warm-Season Fertilizer Schedule: Feed at 65-85°F Soil

Bermuda, zoysia, St. Augustine, centipede, and bahia each have a different nitrogen budget and a different green-up trigger. Feed too early or too late and you invite winterkill, thatch, and disease. This guide ties every application to soil temperature and species, with rates and last-safe-feeding dates sourced from 15+ university turfgrass extensions.

When to Stop Mowing Before Winter Dormancy

Use soil temperature, not the calendar, to time your final mow. Cool-season turf stops near sustained 45°F soil; warm-season near 55-60°F. Get the final cut height right, clear the leaves to beat snow mold, and time the winterizer. Step-by-step guide sourced from 15+ university turfgrass extensions.

Winter Dormancy Lawn Care: What to Do and Not Do

Brown winter turf is dormant, not dead. Learn the soil-temperature thresholds that trigger dormancy, when winter watering helps versus harms, how to time a potassium-rich winterizer, and how to prevent snow mold and winterkill. Step-by-step guide sourced from 15+ university turfgrass extensions.

Affordable Lawn Renovation: A New Homeowner's Guide for Cool-Season Lawns

You just bought a house with a neglected lawn. Three season-branched action plans for fixing it on a $265 to $787 first-year budget, sourced from 13 university turfgrass extensions. Tied to your local soil temperature data.

When to Apply Broadleaf Weed Killer on Cool-Season Lawns in Spring

Spring broadleaf timing for Kentucky bluegrass, fescue, perennial ryegrass, and the cool-season blends. Wait for steady 60-85°F air temps and actively growing weeds. Step-by-step timing guide sourced from 18 university turfgrass extensions.

When to Apply Broadleaf Weed Killer on Warm-Season Lawns in Spring

Spring broadleaf timing for St. Augustine, centipede, bermuda, zoysia, and bahia. Wait for full green-up, mow twice, then spray under 85°F. Per-grass chemistry guide sourced from 12+ Southern university turf extensions.

How to Identify and Kill Nutsedge in Your Lawn

Nutsedge is a sedge, not a grass, which is why standard weed control fails. Identify yellow vs. purple nutsedge and time herbicides by soil temperature.

Spring Lawn Fertilization: Start at 55°F Soil Temperature

Use soil temperature, not the calendar, to time your spring fertilizer. Research-backed rates, NPK ratios, and grass-type-specific guidance from 20+ university turfgrass programs.

When to Overseed Your Lawn in Spring: The 50-65°F Window

Overseed in spring once 2-inch soil holds 50-65°F, before it reaches 70°F. Use fast-germinating perennial ryegrass or tall fescue, pair with a seeding-safe pre-emergent like Tenacity, and water daily for the first month. Step-by-step guide sourced from 15+ university turfgrass extensions.

How to Apply Liquid Pre-Emergent Herbicide

Learn how to mix, calibrate, and spray liquid pre-emergent herbicide. Covers sprayer setup, flat-fan nozzles, and watering-in backed by university research.

When to Apply Pre-Emergent: Soil Temperature Timing Guide (50–55°F)

When to apply pre-emergent: when 2-inch soil temperature holds 50–55°F. A soil-temperature timing guide for crabgrass prevention, with product picks.