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The Calculators.

133 calculators, guides, and reference tools · Use them in the browser, embed them anywhere

Tools: 133
Grouped by: 15 domains
Cost: Free, no account, no signup
Curated paths: Each growing topic links its own tools

Every tool runs right in the browser. No account, no install. Browse by domain below, or filter to find one fast. Each growing topic also links the tools for its own domain.

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Light & photoperiod 13

Cost-per-DLI Calculator

What does it cost to deliver target DLI in your room? The economic-decision metric for fixture selection.

Light & photoperiod

Day/Night DIF Designer

Day-night temperature differential. Control stretch and morphology without chemical PGRs.

Light & photoperiod

Daylight Calculator

Sunrise, sunset, day length, and photoperiod-trigger flagging by latitude and date.

Light & photoperiod

DLC QPL Reference

DesignLights Consortium-listed grow lights. Verify rebate eligibility, PPE thresholds, and Premium-tier qualification.

Light & photoperiod

DLI Calculator

Daily Light Integral from PPFD and photoperiod. Per-cultivar reference targets included.

Light & photoperiod

Fixture Comparison

Compare grow lights: Fluence, Heliospectra, Gavita, ChilLED, HLG, Spider Farmer, HPS, CMH.

Light & photoperiod

Grow Light Studio

One fixture, one room: canopy PPFD, uniformity, DLI, crop fit, and energy cost together.

Light & photoperiod

Latitude Comparison

Compare daylight and DLI across two locations. How does light differ between Tucson and Stockholm?

Light & photoperiod

Photoperiod Trigger Calendar

When will photoperiod-sensitive cultivars trigger flowering at your latitude?

Light & photoperiod

Phytochrome State Calculator

Pfr/Ptotal from R:FR ratio. Spectrum design, EOD-FR planning, stretch management.

Light & photoperiod

PPFD from Distance

Estimate canopy PPFD from fixture spec and hang height. Plan a grow space without buying a meter first.

Light & photoperiod

Solar Curve Visualizer

What the sun does, hour by hour, at any latitude on any date: solar elevation and clear-sky PPFD.

Light & photoperiod

Sunrise/Sunset Ramp

Smooth photoperiod transitions + optional EOD-FR pulse. Reduce stress, accelerate flowering.

Light & photoperiod

Air, climate & CO₂ 11

Air Exchange (ACH)

Air changes per hour from CFM and room volume. Fan and exhaust sizing for indoor spaces.

Air, climate & CO₂

Climate Zone Classifier

USDA hardiness, Köppen, and Open Agriculture Technology cultivation zone. Quick lookup for your location.

Air, climate & CO₂

CO₂ Enrichment

Greenhouse CO₂ injection rate, tank vs generator economics, safety thresholds, yield response.

Air, climate & CO₂

Dew Point Calculator

When and where condensation will form. Pair with VPD for night-setpoint planning.

Air, climate & CO₂

Environment Studio

Author the staged climate for your crop (air temp day/night, humidity, VPD, CO₂, airflow, plus root-zone temp, oxygen, and moisture) against your…

Air, climate & CO₂

Frost Cloth Selector

Row cover weight + frost protection + cost. Pest exclusion, frost extension, hardening-off.

Air, climate & CO₂

Frost Date Calculator

Average last spring and first fall frost dates by USDA hardiness zone or reference city.

Air, climate & CO₂

Frost Tolerance Reference

What dies tonight at 28°F? 50+ crops with kill temps + cover-or-harvest decision support.

Air, climate & CO₂

Growing Degree Days

Predict crop development and pest emergence from accumulated heat units. 25 crop and pest models built in.

Air, climate & CO₂

Shade Cloth Selector

What % shade for what crop. Climate-adjusted, with fabric specs and color guidance.

Air, climate & CO₂

VPD Calculator

Air and leaf vapor pressure deficit with per-stage target bands. The single most important environmental number.

Air, climate & CO₂

Water, nutrients & feed 13

Brix Refractometer Guide

Reference ranges per crop, how to read, what raises Brix. Plant health and harvest indicator.

Water, nutrients & feed

Compatibility Checker

Will these two compounds tank-mix safely? Quick pair-lookup against known incompatibilities.

Water, nutrients & feed

Compound Lookup

Look up any agronomic compound by CAS, formula, or name. Authoritative data from PubChem.

Water, nutrients & feed

Deficiency Symptom Guide

Diagnose nutrient deficiencies by location, color, and symptom. Returns ranked candidate diagnoses across 11 essential elements.

Water, nutrients & feed

Drip Irrigation Designer

Emitter type and spacing, run time, full BOM. Garden through orchard scale.

Water, nutrients & feed

EC / PPM Converter

Convert between EC, PPM-500 (US), and PPM-700 (EU) scales, plus crop reference targets.

Water, nutrients & feed

Foliar Spray Calculator

Foliar feeding rates for 12 nutrients/biostimulants. Tank mix, surfactant guidance, timing rules.

Water, nutrients & feed

Irrigation Schedule

Calculate gallons-per-week and frequency from crop, ET, soil. Compare drip/overhead/furrow efficiency.

Water, nutrients & feed

Nutrient Calculator

Build a recipe from raw compounds. See elemental ppm delivery with compatibility flagging.

Water, nutrients & feed

Nutrient Recipe Builder

Build a feed from salts or commercial products. Full elemental analysis vs your crop's targets, EC estimate, printable recipe sheet.

Water, nutrients & feed

Source Water Decoder

Paste your municipal report or well test. See what your starting water means for nutrient delivery and pH stability.

Water, nutrients & feed

Tank Mix Order Planner

What order to add fertilizers and amendments to your stock or batch tank. Avoid precipitation, lockout, and wasted nutrient.

Water, nutrients & feed

Tissue & Sap Test Reference

Interpret plant tissue analysis. Sufficiency ranges per element by crop, with deficiency symptoms.

Water, nutrients & feed

Substrate & soil 12

Amendment Calculator

Lime, sulfur, gypsum, and nutrient amendments. Per-acre and per-1000ft² rates with timing.

Substrate & soil

Compost C:N Calculator

Build a hot-compost pile with the right carbon-to-nitrogen ratio. 30+ feedstocks; live mix calculator.

Substrate & soil

Compost Pile Sizing

Pile dimensions, capacity, turning frequency. 6 methods from cold pile to commercial windrow.

Substrate & soil

Compost Tea Brewer

Aerated tea recipe + equipment + dilution from 5 to 500 gal. Vermicompost or thermophilic.

Substrate & soil

KNF Brew Calculator

Korean Natural Farming brews: FPJ, FFJ, OHN, IMO, LAB, WCA. Materials, times, dilutions.

Substrate & soil

Pot Size Calculator

Right-size your container. Crop + method + cycle length → recommended size.

Substrate & soil

Soil Moisture Tension

Read your tensiometer / Watermark sensor. Irrigate-now thresholds by 14 crops × soil texture.

Substrate & soil

Soil Test Report Reference

Read your soil test. pH, OM, CEC, base saturation, P, K, Ca, Mg, micronutrients: what to do at each range.

Substrate & soil

Soil Texture Triangle

USDA soil class from sand/silt/clay percentages, with management guidance per class.

Substrate & soil

Substrate Comparison

Compare growing media side-by-side: coco vs peat vs rockwool vs living soil vs hydroponic.

Substrate & soil

Substrate Lifecycle

Cost-over-time of single-use rockwool vs reusable coco vs living soil. Multi-cycle math.

Substrate & soil

Worm Castings Calculator

Bin sizing, worm population, feeding rate, harvest schedule. Red wigglers, ENC, ANC.

Substrate & soil

Structures, greenhouse & energy 21

Battery Bank Sizing

Backwards from the load: daily watt-hours, autonomy, and chemistry in; battery Wh and Ah, worst-month array watts, controller amps out.

Structures, greenhouse & energy

Capacity Calculator

How many plants fit? Sq ft + cultivar + method → recommended count with spacing.

Structures, greenhouse & energy

Composting Toilet Designer

Off-grid sanitation that builds soil. Bucket through commercial-NSF systems. Pathogen die-off + legal status.

Structures, greenhouse & energy

Coverage Layout Designer

Plan grow room fixture layout. Visualize coverage and overlap with top-down room view.

Structures, greenhouse & energy

Greenhouse Cooling Load

Solar heat gain + outdoor + transpiration → BTU and fan CFM sizing for greenhouses.

Structures, greenhouse & energy

Greenhouse Energy Audit

12-item self-audit checklist + retrofit ROI. Compound-savings calculation.

Structures, greenhouse & energy

Greenhouse Heating Cost

Heat-loss BTU and annual fuel cost across 7 fuel types. Compare propane vs heat pump vs cordwood.

Structures, greenhouse & energy

Greenhouse Layout Designer

Beds, paths, headhouse. Top-down SVG view + utilization-rate calculation.

Structures, greenhouse & energy

Greenhouse Light Transmission

How much sunlight reaches your canopy after glazing, structure, age, and shade cloth losses?

Structures, greenhouse & energy

Greenhouse ROI Calculator

Should you build a greenhouse? Capital + opex vs revenue, payback, NPV, IRR. Honest projections.

Structures, greenhouse & energy

Greenhouse Vent Sizing

Natural vent area, exhaust fan CFM, intake shutters, and evap cooling pad sizing for any climate.

Structures, greenhouse & energy

Greywater System Designer

Household water reuse for landscape irrigation. Yield, basin sizing, soap chemistry, plant compatibility.

Structures, greenhouse & energy

Hoop House Designer

Low tunnel through NRCS-spec high tunnel. Snow load engineering + EQIP cost-share path.

Structures, greenhouse & energy

HVAC Cost Estimator

Lighting heat + transpiration → BTU load → kWh → monthly cost. Indoor cultivation reality check.

Structures, greenhouse & energy

Insulation R-Value

Stack up wall layers; calculate combined R + U. 21 materials from spray foam to greenhouse plastic.

Structures, greenhouse & energy

Multi-Zone Visualizer

See your whole facility at once: per-zone setpoints across 5 facility configurations.

Structures, greenhouse & energy

Passive Solar Greenhouse

Chinese-style + earth-bermed designs. Glazing angle, thermal mass, latitude-specific guidance.

Structures, greenhouse & energy

Pressure Cascade Designer

Negative-pressure airflow visualization for multi-zone facilities. Odor + pathogen control.

Structures, greenhouse & energy

Rainwater Catchment

Rainfall capture from your roof, monthly catchment vs demand, tank sizing, first-flush diverter sizing.

Structures, greenhouse & energy

Solar Pump Sizing

Off-grid water pumping. TDH math, pump type recommendation, panel + battery + tank sizing, full BOM.

Structures, greenhouse & energy

Wire & Fuse Sizing

Size copper wire and its fuse for a DC circuit. Load, run length, and voltage drop in; AWG, actual drop, and fuse rating out.

Structures, greenhouse & energy

Field, beds & planting 14

Companion Planting Reference

What to plant together, and apart. 15 vegetables and herbs with mechanism-grounded recommendations.

Field, beds & planting

Cover Crop Selector

Match the cover crop to your goal: fix N, build OM, suppress weeds, biofumigate. 30+ species filtered.

Field, beds & planting

Field Border Designer

Riparian buffers, hedgerows, pollinator strips. USDA cost-share program guide (CRP, EQIP, CSP).

Field, beds & planting

Field Rotation Planner

Multi-year crop rotation for soil health and pest pressure reduction. 5 templates.

Field, beds & planting

Forest Garden Designer

7-layer perennial polyculture with regional plant recommendations and 10-year establishment timeline.

Field, beds & planting

Hugelkultur Designer

Wood-core mound design. Materials BOM, wood selection, 5-year planting plan.

Field, beds & planting

Mulch Calculator

Volume of mulch needed for any area + depth. Cost across 12 mulch types: wood chip, straw, compost, gravel.

Field, beds & planting

Orchard Tree Spacing

Trees per acre, pollination partners, training systems. 20 fruits + nuts; backyard through commercial.

Field, beds & planting

Plant Spacing Layout

Bed dimensions + crop + spacing method → plant count, top-down visual, yield. Row, square-foot, or bio-intensive.

Field, beds & planting

Seed Starting Calendar

When to start indoors, when to direct-sow, when to transplant, for 30+ vegetables based on your last frost date.

Field, beds & planting

Stagger Planner

Continuous-harvest scheduling across multiple grow rooms. Visualizes a year of staggered cycles.

Field, beds & planting

Tractor Implement Sizing

Match tractor PTO HP + 3-point hitch category to 14 common implements.

Field, beds & planting

Tree Pruning Calendar

When to prune what. 35+ species across fruit trees, ornamentals, shrubs, vines.

Field, beds & planting

Windbreak Designer

Multi-row shelterbelt design with regional species, 15H protection geometry, and establishment timeline.

Field, beds & planting

Crops & cultivars 5

Crop Risk Assessment

Self-score 12 risk dimensions (frost, drought, pest, market, labor). Surface what's likely to fail; pick mitigation.

Crops & cultivars

Cultivar Browser

40-cultivar searchable reference across cannabis, tomato, lettuce, mushroom, and more.

Crops & cultivars

Disease Resistance Lookup

Find resistant cultivars by crop and disease. Tomato VFN codes, downy mildew, late blight, decoded.

Crops & cultivars

Plant Recipe Browser

Community-shared cultivation recipes: cannabis, tomato, lettuce, mushroom, etc. Forkable, attributed.

Crops & cultivars

Yield Estimator

Crop + method + experience + count → realistic yield range. For planning, not guarantees.

Crops & cultivars

Specialty crops 6

Cut Flower Production

Stems-per-bed for 20 flower varieties. Sales channel pricing, post-harvest, vase life.

Specialty crops

Hop Trellis Planner

Design a hop yard. Trellis style, row spacing, plant count, materials BOM, expected yield over 3+ years.

Specialty crops

Maple Syrup Production

Sugarbush yield, evaporator boil time, BOM, and economics. 7 species + 4 evaporator tiers.

Specialty crops

Microgreens Production Math

Tray density, days to harvest, weight per tray, COGS, weekly + annual revenue for 23 varieties.

Specialty crops

Training Methods

Topping, FIM, LST, ScrOG, super-cropping, mainlining: when, how, what trade-offs.

Specialty crops

Trichome Maturity Guide

When to harvest cannabis. Trichome head color (clear/cloudy/amber) and effect-profile timing.

Specialty crops

Bees & pollinators 7

Apiary Site Survey

12-factor scoring for evaluating hive locations. Stack rank multiple sites; identify weakest factors.

Bees & pollinators

Bee Disease Reference

Diagnose hive problems by symptom or disease. Varroa, AFB, EFB, and 9 more, with treatment + reporting.

Bees & pollinators

Bee Forage Selector

Year-round nectar plants. 40+ species filtered by region, season, and pollinator type. Build a no-gap forage calendar.

Bees & pollinators

Beehive Yield Estimator

Honey + secondary product projection by region, management style, and experience. Realistic apiary economics.

Bees & pollinators

Beekeeping Calendar

Month-by-month hive management across 7 regions. Critical-task callouts.

Bees & pollinators

Pollination Service

Hives per acre by crop. Rental costs, native bee + mason bee + bumble alternatives.

Bees & pollinators

Pollinator Garden Designer

Continuous-bloom calendar across 5 seasons with regional natives and pollinator-targeted filtering.

Bees & pollinators

Livestock & pasture 9

Animal Birth Calendar

Gestation + incubation due dates for 23 species. Cattle, sheep, goats, poultry, exotics. With pre/post schedules.

Livestock & pasture

Brooder Calculator

Brooder space, heat, feed, water, and timeline for chicks, ducklings, poults, goslings, quail.

Livestock & pasture

Egg Production Estimator

Eggs per week + economics from a layer flock. 12 breeds, age curve, seasonal variation, feed-per-egg.

Livestock & pasture

Forage Quality Calculator

Read your hay analysis. RFV, TDN, animal-class adequacy from CP/ADF/NDF inputs.

Livestock & pasture

Goat Browse Reference

What goats eat, and don't. ~50 plants across favorites, invasive control, and lethal toxics.

Livestock & pasture

Heritage Breed Selector

~50 conservation-status livestock breeds filtered by species × purpose × climate × scale.

Livestock & pasture

Manure Management

Annual production, storage sizing, NPK content, application acres. CAFO threshold check.

Livestock & pasture

Pasture Forage Mix Builder

Grass + legume + forb mix tailored to region, livestock, and grazing intensity. Establishment cost included.

Livestock & pasture

Pasture Stocking Density

AU-based grazing capacity with rotational paddock math, recovery time, and continuous-vs-mob comparison.

Livestock & pasture

Mushrooms & aquaculture 5

Aquaculture Tank Calculator

RAS sizing: fish-only system. 10 species, biofilter, oxygen, pumps, heater/chiller, full BOM.

Mushrooms & aquaculture

Aquaponic Stocking Density

Balance fish biomass, grow bed area, and biofilter capacity. Tilapia, trout, perch, catfish.

Mushrooms & aquaculture

Grain Spawn Recipe

Mushroom grain spawn batches (rye, millet, wheat, popcorn): hydration, sterilization, transfer math.

Mushrooms & aquaculture

Mushroom Substrate Recipe

Build tested substrate for oyster, lion's mane, shiitake, king trumpet, reishi, and 5 more gourmet species.

Mushrooms & aquaculture

Mushroom Yield Estimator

Multi-flush yield by 10 species. Annual production from blocks/week, full P&L.

Mushrooms & aquaculture

Plant health & IPM 4

IPM Beneficial Selector

For each pest (spider mites, aphids, thrips, whitefly, fungus gnats, more), what predator or parasitoid actually works.

Plant health & IPM

Pathogen Pressure Forecast

Botrytis, powdery mildew, spider mites, Pythium: pressure index from your environmental conditions.

Plant health & IPM

Pest & Disease ID Guide

Identify 25+ pests and diseases: symptoms, where to find them, environmental drivers, and controls.

Plant health & IPM

Pesticide Spray Calculator

Tank mix amounts, unit conversions, calibration. Backpack through tractor sprayer.

Plant health & IPM

Post-harvest 3

Drying & Curing Schedule

Day-by-day RH and temp curve for proper dry / cure. Cannabis, hops, herbs, mushrooms.

Drying Yield Loss

Fresh-to-dry conversion for 17 crops. Moisture math, drying time, fresh-vs-dry revenue comparison.

Winter Storage Calculator

Plan to feed your household from your harvest. Per-crop targets, storage conditions, root cellar sizing.

Sensors & monitoring 3

Camera Resolution Calculator

Millimeters per pixel from camera + framing, and a plain verdict: canopy yes, aphids maybe, mites no.

Sensors & monitoring

Hardware Build Configs

DIY sensor builds. Walk-in cooler monitor, greenhouse multi-zone, beehive scale, more. Under $100 typical.

Sensors & monitoring

Sensor Comparison

Pick the right sensor: temp, humidity, CO₂, pH, EC, PAR. Spec, accuracy, Open Agriculture Technology compatibility.

Sensors & monitoring

Business, energy & compliance 7

Carbon Footprint Estimator

CO₂e per pound of harvested product. Energy + nutrients + transport + substrate broken down by source.

Business, energy & compliance

Compliance Readiness

Self-assess audit readiness for NOP, FSMA 204, METRC, GlobalG.A.P., Real Organic.

Business, energy & compliance

Cycle COGS Calculator

Per-cycle cost-of-goods-sold across inputs, energy, labor, water, and overhead. Reality-check your economics.

Business, energy & compliance

OMRI Status Lookup

Quick reference for USDA NOP organic compliance: fertilizers, amendments, pesticides, microbes.

Business, energy & compliance

PHI / REI Lookup

Pre-Harvest Interval and Re-Entry Interval for common pesticides (organic and conventional).

Business, energy & compliance

Worker Safety CO₂

Safe entry levels and purge time for CO₂-enriched grow rooms. OSHA limits + ventilation math.

Business, energy & compliance

Worker Safety Reference

OSHA + EPA WPS: pesticide PPE, heat illness, machinery, confined space, zoonosis, recordkeeping.

Business, energy & compliance