The HarvestMath blog

How to Harvest Lettuce: Leaf, Romaine and Butterhead

How to harvest lettuce: pick outer leaves at 4 to 6 inches, cut romaine at 6 to 8 inches, go early. Cut-and-come-again regrowth, bolting, storage and seed.

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A white calla lily with funnel-shaped flowers and glossy arrowhead leaves in a pot beside a bright window

How to Look After a Calla Lily: Indoor and Garden Care

How to look after a calla lily: bright light, evenly moist soil, monthly feeding, then a dry winter rest for the rhizome, per extension advice.

Whole golden yellow spaghetti squash and two cut halves showing pale strands on a rustic wooden shelf

How Long Is Spaghetti Squash Good For? Storage Guide

How long is spaghetti squash good for? Extension sources say whole fruit keeps about 2 to 3 months, cut pieces 5 days and cooked leftovers 3 to 4 days.

Yellow crookneck squash and a dark green acorn squash growing among broad leaves in a raised bed vegetable garden

How to Grow Squash: Planting, Spacing and Harvest

How to grow squash: sow in warm soil after frost, space by vine type, pick summer squash young and winter squash hard-rinded. Extension numbers inside.

A young staked apple tree with a few spring blossoms in a home orchard row

How Long Does an Apple Tree Take to Grow?

How long does an apple tree take to grow? Dwarf trees fruit in 2 to 3 years, standard trees in 6 to 10. Size, spacing, lifespan and how to speed it up.

Bunches of statice, larkspur, zinnias and roses hanging upside down to dry from a wooden rack in a dim shed, some already papery and dried

How to Dry Flowers: Hanging, Silica Gel, Pressing

How to dry flowers: hang small bunches upside down for 2 to 3 weeks, use silica gel for days, or press flat. Statice, tulips, daisies, wildflowers.

Hands using small snips to cut cilantro stems about two inches above the soil in a sunny raised bed, with a small basket nearby

How to Snip Cilantro: Harvest, Regrow and Store

How to snip cilantro: cut outer stems at 4 to 6 inches, or the whole plant 1 to 2 inches above soil. Regrowth, bolting, coriander seed and storage.

A healthy aloe vera in a terracotta pot on a bright windowsill with a watering can pouring slowly onto dry, gritty soil

How Often to Water Aloe Vera: A Sourced Schedule

How often to water aloe vera: when the soil is dry, about weekly in summer and every 2 to 3 weeks in winter. Extension advice on soil, pots and warning signs.

A red poinsettia in a green nursery pot with its foil sleeve removed, being watered in a kitchen sink and draining from the bottom holes

How Often to Water Poinsettia: A Simple Routine

How often to water poinsettia: when the soil surface feels dry, not on a set day. Sink and drain method, foil sleeves, and signs of over or underwatering.

A staked tomato vine in morning light with yellow flowers, green fruit and ripening red tomatoes on the same truss

How Long Do Tomatoes Take to Grow? Seed to Ripe Fruit

How long do tomatoes take to grow? About 5 to 8 weeks as seedlings, then 50 to 85 days from transplant to ripe fruit. Timelines by type, from extension.

Hands pressing marigold seeds into a seed tray of moist potting mix beside a row of young seedlings

How to Plant Marigold Seeds: Depth, Timing, Spacing

How to plant marigold seeds: sow 1/4 inch deep after frost, or start indoors 4 to 8 weeks early. Extension spacing, germination and bloom times.

Orange pumpkins ripening among large green leaves and long sprawling vines in a sunny vegetable garden in early autumn

How to Grow Pumpkins: Timing, Spacing and Care

How to grow pumpkins: plant after frost in warm soil, give each hill 40 to 64 square feet, water deeply, and allow 90 to 120 days. Extension numbers inside.

Thick green asparagus spears rising from mulched soil in a garden bed beside a row of tall feathery asparagus ferns

How Does Asparagus Grow? Planting and Care Guide

How does asparagus grow? A perennial that sends up spears from crowns, then ferns, with a light harvest in year 2 or 3. Planting, care and fall cutback.

A row of mature English lavender plants in full bloom with purple flower spikes growing in pale gravelly soil beside a sunny garden path

Lavender How To: Plant and Care for It

Lavender how to: full sun, fast-draining soil, 18 to 36 inches between plants and light pruning. Extension advice on timing, pots, varieties and Florida.

A young pomegranate tree with glossy green leaves and orange-red blossoms newly planted in a sunny garden bed, with a ring of wood chip mulch around the base

How Do You Plant a Pomegranate? Tree Planting Guide

How do you plant a pomegranate? Plant in early spring in full sun, in a hole 2 to 3 times the root ball width. Spacing, size, years to fruit and care.

Gloved hands holding red-handled bypass pruners at a dry hydrangea stem, with brown faded flower heads and a few yellow leaves in the autumn garden behind

How to Cut Back Hydrangeas: Timing by Type

How to cut back hydrangeas depends on the type: panicle and smooth in late winter, bigleaf and oakleaf right after bloom. Extension timing, heights and cuts.

A pink-flowered Phalaenopsis orchid in a clear pot with silvery green roots visible, being watered from a small white can on a window sill

How to Water Orchids: The Soak and Drain Method

How to water orchids: soak the pot with lukewarm water, drain it fully, repeat about weekly in bark. Extension root-color cues and the ice cube debate.

Gloved hands holding pruners to cut a faded purple lilac flower cluster just below the bloom, with fresh green leaves behind

How to Prune a Lilac Bush: When and How Much

How to prune a lilac bush: deadhead right after bloom, then thin the oldest third of the stems over three years. Extension timing, heights and rejuvenation.

A ripe magenta dragon fruit with green-tipped scales beside a cut half showing white flesh with black seeds on a wooden table

How to Tell if a Dragon Fruit Is Ripe (Store or Vine)

How to tell if a dragon fruit is ripe: full color, a heavy feel and skin that is firm but slightly soft. Extension harvest days, storage and spoilage.

A hand holding pruning shears to clip the short stem of a deep red pomegranate on the tree in warm autumn light, with leaves and other fruit behind

How to Pick Pomegranate Fruit: Timing and Tools

How to pick pomegranate fruit: wait for full maturity, clip the stem close to the fruit and handle gently. Extension harvest months, passes and storage.

A pile of freshly dug red and gold potatoes on dark soil beside a mounded row of green potato vines, with a garden fork standing in the background

How Do You Grow Potatoes? Planting to Harvest

How do you grow potatoes? Plant certified seed 3 to 5 inches deep and 10 to 12 inches apart, hill as they grow, and dig in 90 to 120 days.

Best Tomato Fertilizer: 7 Types Ranked and Compared

Best tomato fertilizer by type: compost, balanced granular, nitrogen side-dress, liquid, slow-release and organic. N-P-K, schedule and amount per plant.

Deep red ripe pomegranates hanging on a branch in autumn, one with slightly flattened sides and a dried crown at the top

How to Tell if a Pomegranate Is Ripe (Tree or Store)

How to tell if a pomegranate is ripe: check sides, crown, skin and tap sound on the tree, or weight at the store. Harvest months and spoilage signs.

A fingertip testing the dry gritty soil of a terracotta pot of echeveria and haworthia on a bright windowsill, beside a glazed pot of jade plant

How Often Do You Water Succulents? A Schedule Guide

How often do you water succulents? It shifts with season, light, pot and soil. A sourced schedule table for indoors, outdoors, winter and summer.

Freshly dug peanut plants with soil-covered pods hanging from the roots, laid on the ground of a sunny garden bed in early autumn

How to Grow Peanuts: Planting, Spacing and Harvest

How to grow peanuts: sow seed 1 to 2 inches deep in warm soil after frost, then dig in 120 to 150 days. Spacing, calcium, hilling, curing and containers.

Two plant root systems side by side, one with brown, soft, rotted roots and one with firm white healthy roots

How to Fix Root Rot: Signs, Rescue Steps, Prevention

Wilting in wet soil plus brown, mushy roots means root rot. Extension-backed steps to check roots, trim, repot in fresh mix, and keep it from coming back.

Young seedlings in a seed-starting tray with thin stems collapsed and lying flat on the soil beside upright neighbors

How to Prevent Damping Off: Causes, Signs and Fixes

Damping off rots seeds and collapses seedlings at the soil line. Learn the causes, how to tell it from other failures, and what extension research backs.

Tall, thin tomato seedlings in cell trays leaning toward a bright window, with long thin stems and small leaves

How to Prevent Leggy Seedlings: Light, Heat, Rescue

Leggy seedlings are stretching for light. Extension advice on lamp height, daily light hours, cooler nights, airflow, and burying tomato stems to rescue them.

Tomato flower truss with yellow blossoms shriveling on the stem before any fruit has formed

How to Fix Blossom Drop on Tomatoes: Heat and Water

Tomato flowers falling off before fruit sets is usually heat, cold nights, dry soil or poor pollination. Extension temperature limits and what to do.

Soil Bulk Density: Formula, Core Test and Garden Ranges

Soil bulk density is dry soil mass divided by volume. Get the formula, a pipe core method with a worked example, and the USDA ranges that matter for roots.

Soil Profile and Horizons: O, A, E, B, C and R Explained

Soil profile horizons explained: what the O, A, E, B, C and R layers are, how thick topsoil runs, and what each layer means for roots and raised beds.

A gloved hand holding a digital probe thermometer over dark, moist soil in a raised vegetable bed with small lettuce seedlings and a wooden row marker in early morning light

Soil Temperature for Planting: Minimums and How to Check

Soil temperature for planting: minimums for 15 vegetables from Alabama and Wisconsin Extension, how to take a reading, and where to find local data.

Potting bench beside a spring garden with a blank notebook, seed packets, tomato seedlings, a thermometer and a rain gauge

Farmer's Almanac Frost Dates vs. NOAA Data

The Farmer's Almanac frost dates come from NOAA's 1991-2020 normals. See how they compare with nearest-station median and 1-in-10 dates in 5 U.S. cities.

A small copper watering can soaking the soil of a terracotta pot of echeveria succulents on a bright windowsill, with water beginning to run out of the drainage hole

How to Water Succulents: Soak, Dry and Repeat

How to water succulents: soak until water drains, then wait for the mix to dry. How often, how much, pots, indoor and winter care, with extension sources.

A husked mango seed sprouting a pale green shoot with red-tinged first leaves from dark potting mix in a small nursery pot in bright natural light

How to Plant Mangoes From Seeds: Sprout to Tree

How to plant mangoes from seeds: husk the pit, sow it 1/2 to 1 inch deep, expect 2 to 3 weeks to sprout and 5 or more years to fruit. Zones 10 and 11.

A healthy aloe vera plant in a terracotta pot on a sunny windowsill, with a small pup at its base and two separated pups drying on a wooden table beside a clean knife

How Do I Grow Aloe Vera Plants? Care and Propagation

How do I grow aloe vera plants? Use gritty cactus mix, bright light and water only when dry. Propagate from pups; extension is cautious about single leaves.

Callused echeveria stem cuttings and a few loose fleshy leaves resting on a wooden tray beside a small terracotta pot of gritty cactus mix holding one freshly planted cutting

How to Grow Succulents From Cuttings, Step by Step

How to grow succulents from cuttings: cut a 3 to 6 inch stem, let it callus for several days, root it in gritty mix. Leaves, pups, timing and care.

Mature green and blushing tomatoes spaced in a single layer in a shallow cardboard box lined with newspaper, on a wooden shelf in soft indirect light, with one fully red tomato beside them

How to Ripen Green Tomatoes Indoors and Off the Vine

How to ripen green tomatoes: pick mature greens before frost, keep them warm and out of direct sun, and expect about 2 weeks. What ripens, what won't.

White frost crystals on kale and lettuce leaves in a garden bed at sunrise

What Temperature Is Frost? Why It Forms Above 32°F

Frost forms when surfaces hit 32°F, yet it can coat your garden at a forecast low of 36°F. Why it happens, what NWS alerts mean, and how to protect plants.

A gloved hand pressing a small yellow onion set, pointed tip up, into a shallow furrow of dark garden soil beside a row of sets already planted about three inches apart

How to Plant Onion Sets: Depth, Spacing and Dates

How to plant onion sets: 1 inch deep, 3 to 4 inches apart, as soon as the soil can be worked. Zones 5 to 7, fall planting, pots, raised beds and big bulbs.

Watering

How Often to Water Tomatoes: Amounts and Schedule

How often to water tomato plants: 1 to 1 1/2 inches a week in deep soaks, in the morning. Schedules for pots, raised beds, hot weather, drip and greenhouses.

Lawn

When to Overseed Lawn: Best Timing by Grass Type

When to overseed lawn grass: the soil temperatures and dates for cool-season and warm-season lawns, how late is too late, and which seed to use where.

Gloved hands spreading straw mulch over a raised vegetable bed in late autumn, with kale still standing, fallen leaves and a coiled hose beside it

How to Winterize Your Garden: 7 Steps by Frost Date

How to winterize your garden in 7 steps: clear and bin diseased plants, test soil, mulch, sow cover crops, protect plants, drain hoses. By frost date.

A hand using kitchen scissors to snip outer cilantro stems about two inches above the soil in a raised garden bed

How to Grow Cilantro: Planting, Care and Bolting

How to grow cilantro: sow seed 1/4 to 1/2 inch deep in cool weather, thin to 6 to 8 inches, harvest in 45 to 70 days. Pots, bolting, Florida and Texas.

Lawn

How to Reseed a Lawn: Steps, Seed Rates and Watering

How to reseed a lawn or overseed a thin one: when to start, how to prep the soil, seed rates by grass type, starter fertilizer, watering and first mow.

Freshly dug hardneck garlic with roots and partly browned leaves laid on the soil beside a garden fork

When to Harvest Garlic: Signs, Digging and Curing

Harvest garlic when the lower leaves turn brown but about half the leaves are still green, usually June or July. How to dig, cure and store the bulbs.

Gardener pressing garlic cloves pointed end up into loose soil in a raised bed in autumn, with straw mulch nearby

How to Plant Garlic: Timing, Depth and Spacing

Plant garlic cloves in fall, pointed end up, 2 to 3 inches deep and about 6 inches apart. Timing by region, mulch, and how many cloves fill a 4x8 bed.

How to Fill a Raised Garden Bed (Without Overspending)

The real raised bed soil mix, and how to fill a raised garden bed without buying the full depth in bagged soil -- what actually saves money, what to skip, and how much to expect it to settle.

How Much Soil for a 4x8 Raised Bed (Full Chart)

32 cubic feet of soil fills a 4x8 raised bed at 12 inches deep -- exact amounts for every depth, in cubic feet, cubic yards, and bags, plus what actually fits once it's planted.

Several nursery plant pots of different sizes lined up in a row

Plant Pot Sizes Chart: Gallon Dimensions and Volume

Plant pot sizes chart for 1 to 20 gallon nursery pots: typical diameter, height and soil volume in quarts and litres, plus how to measure a plant pot.

A man with a backpack measuring the circumference of a large oak tree trunk with a yellow tape measure in a forest

How to Tell the Age of a Tree (3 Real Methods, Compared)

Ring counting, increment boring, or circumference math -- three real ways to age a tree, and which one actually fits your situation.

Healthy garden bed with a variety of plants, for understanding USDA hardiness zones

Understanding USDA Hardiness Zones: What They Actually Mean

What a hardiness zone actually measures, why it's not the whole picture, and what you can realistically grow in yours.

Tomato with dark, leathery, sunken patch at the blossom end, showing classic blossom end rot

Blossom End Rot: Why It Happens and How to Actually Fix It

Usually not a calcium problem -- the real cause is inconsistent watering. Here's how to actually stop blossom end rot on tomatoes, peppers, zucchini, and watermelon.

Plant leaf covered in white powdery fungal coating, for identifying powdery mildew

Powdery Mildew: How to Identify, Treat, and Prevent It

Identify powdery mildew fast, tell it apart from downy mildew and harmless soil mold, then treat it with what actually works.

Houseplant leaf with brown crispy tips, for diagnosing why plant leaf tips are turning brown

Why Are the Tips of My Plants Turning Brown? A Diagnostic Guide

Diagnose brown, crispy leaf tips fast -- tips-only vs. whole-leaf browning, tap water minerals, root-bound roots, and the fix for each.

Leaf with irregular chewed holes, for diagnosing what's causing holes in plant leaves

Why Are There Holes in My Plant Leaves? A Diagnostic Guide

Diagnose holes in plant leaves fast -- bugs vs. no bugs, ragged vs. round, natural fenestration vs. real damage, plus the fix for each.

Wilted houseplant with drooping leaves on a windowsill, for diagnosing why a plant is wilting

Why Is My Plant Wilting? A Diagnostic Guide

Diagnose wilting or drooping leaves fast -- sudden vs. gradual, soil-wet vs. soil-dry, plus the real fix for each cause.

Houseplant leaf with yellowing between the veins, for diagnosing why plant leaves turn yellow

Why Are My Plant Leaves Turning Yellow? A Diagnostic Guide

Why are my plant leaves turning yellow? Diagnose by pattern -- old leaves vs. new, whole-leaf vs. between the veins -- to find the real cause and fix.

A modest backyard vegetable garden with raised wooden beds growing lettuce, tomatoes, and pole beans on a bamboo trellis, gardening tools nearby

How to Start a Vegetable Garden: A Complete Beginner's Guide

Start your first vegetable garden -- how to pick the spot, size it right, prep the soil, and choose what to plant first.

Tomato plant with yellowing lower leaves supported by bamboo stakes and wire cages in a raised garden bed, healthy green growth and flowers above

Why Are My Tomato Leaves Turning Yellow? A Diagnostic Guide

Diagnose yellowing tomato leaves by symptom -- bottom-up yellowing, spots, or curling each point to a different cause and fix.

Tomato plants supported by wire cages and bamboo stakes growing in a wooden raised garden bed, with ripening red and green fruit

Growing Tomatoes in Raised Beds: Spacing, Depth, and Blossom End Rot

Tomato spacing and bed depth for raised beds -- plus why raised beds get blossom end rot more often, and how to prevent it.

Pole bean vines climbing a wooden trellis in a raised garden bed, with mature green bean pods hanging among the leaves and yellow flowers

How to Grow Beans from Seed (Bush, Pole, and the Nitrogen Myth)

Beans are easy to germinate. Here's bush vs. pole, and an honest correction on what beans really do for soil nitrogen.

Cucumber vines climbing a wire trellis in a raised garden bed, with several ripening cucumbers hanging among the leaves and yellow flowers

How to Grow Cucumbers from Seed (and Why Yours Aren't Fruiting)

Cucumbers are easy to germinate. The real problem is pollination -- here's why they flower without fruiting, and the fix.

A bunch of freshly harvested carrots with soil still clinging to the roots, laid on top of a raised garden bed

How to Grow Carrots from Seed (and Actually Get Them to Germinate)

Carrot seeds are slow and finicky. Here's the board method that fixes germination, plus how to avoid forked carrots.

Rows of mature butterhead and red leaf lettuce growing in a raised garden bed

How to Grow Lettuce from Seed: The Cool-Season Crop That Breaks the Rules

Lettuce seeds need light to germinate and refuse to sprout in heat. Here's how to actually grow lettuce from seed.

Trays of young pepper seedlings under a full-spectrum LED grow light on a wire shelving rack

How to Grow Peppers from Seed: Bell, Hot, and Sweet Varieties

Start peppers from seed -- germination temps, why peppers need longer than tomatoes, and the transplant mistake to avoid.

Trays of young tomato and pepper seedlings under a full-spectrum LED grow light, with hand-lettered plant labels including 'Tomato - San Marzano'

How to Grow Tomatoes from Seed: A Complete Guide

Start tomatoes from seed successfully -- germination temps, the heat mat mistake to avoid, and when to transplant.

A black LED grow light panel hanging over a windowsill of seedling trays and houseplants including pileas, snake plants, marigolds, and tomato seedlings

LED vs. Fluorescent Grow Lights: Which Should You Use?

LED and fluorescent grow lights compared -- efficiency, cost, lifespan, and which is actually right for houseplants and seedlings.

An open wooden compost bin filled with fruit and vegetable scraps, eggshells, banana peels, citrus rinds, and dry leaves, set in a garden

What Can (and Can't) You Compost? The Complete List

What you can and can't put in your compost bin -- including surprising yeses like bread, and the real reasons behind the no's.

A potting bench with a bowl of used coffee grounds, a dish of crushed eggshells, overripe bananas, a potted basil seedling, and a labeled jar of compost materials

15 Homemade Fertilizers You Can Make at Home (and How to Mix Them)

Real homemade fertilizers that work, with honest cautions on wood ash and fresh manure -- not just vague "use carefully" warnings.

A raised garden bed mixing tomatoes, basil, marigolds, chard, carrots, and rosemary together in the same planting area

Companion Planting Chart: What to Grow Together (and What to Avoid)

A complete companion planting chart for vegetables and herbs — plus which pairings to avoid and why.

A garden bed split down the middle, showing wood chip mulch on one side and river rock gravel on the other, each surrounding the same planting bed

Organic vs. Inorganic Mulch: Which Is Right for Your Garden?

Organic and inorganic mulch solve different problems. Here's the real difference, and which one your garden actually needs.

A soil test report on a clipboard next to a labeled bag of a submitted soil sample on a potting bench

How to Read and Understand Your Soil Test Results

Soil test numbers explained — pH, organic matter, N-P-K, and how to turn them into an actual fertilizer plan.

A raised bed garden showing succession planting in progress: young lettuce and carrot seedlings alongside maturing kale, chard, and beans at different growth stages

Succession Planting: How to Get More Harvests From the Same Space

Succession planting means more harvests from the same garden space. Here are the three real methods, with examples.

A lush, densely planted shade garden bed of hostas, ferns, and hydrangeas showing healthy, properly fertilized growth

8 Fertilizing Mistakes That Are Hurting Your Garden and Lawn

The most common fertilizing mistakes — from over-application to bad timing — and exactly how to avoid and fix each one.

Labeled diagram of a rain barrel system showing the downspout, diverter, first-flush chamber, rain barrel, spigot, and overflow hose routed away from the foundation

Watering

How to Build a Rainwater Collection System for Your Garden

A step-by-step guide to setting up a rain barrel system — downspout connection, first-flush filtering, and overflow, done right.

A young tree properly mulched with a flat, donut-shaped ring pulled back from the trunk, leaving the root flare and bark clear of mulch

8 Mulch Mistakes That Are Secretly Hurting Your Plants

The most common mulching mistakes — from volcano mulching to guessing the amount — and exactly how to avoid each one.

Lawn

Cool-Season vs. Warm-Season Grass: Which Type Do You Have?

The real difference between cool-season and warm-season grass — including what to plant if you're in the transition zone.