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Crop Timeline Calculator

Enter your last frost date and select a crop to generate a personalised week-by-week growing schedule — from first sow to final harvest.

Your Growing Details

How it works

1

Enter your frost date

Use your average last spring frost date — this anchors your entire season.

2

Pick a crop

Choose from vegetables, herbs or flowers from the dropdown.

3

Get your schedule

We calculate sow indoors, transplant and harvest windows automatically.

What Is a Crop Timeline Calculator?

A crop timeline calculator turns your last frost date into a personalised, week-by-week growing schedule for any crop.

Instead of manually cross-referencing seed packets, planting calendars and hardiness zone charts, you enter one date and get every key milestone — sowing indoors, transplanting outside and your first expected harvest — calculated automatically.

Gardeners use timeline calculators to eliminate the most common cause of crop failure: mistiming. Sowing tomatoes six weeks too early means leggy, root-bound seedlings by transplant day.

A clear, date-anchored schedule removes the guesswork and gives you a realistic picture of your entire growing season in seconds.

Our calculator covers over 30 crops across vegetables, herbs and flowers, each with individual timing data built from standard horticultural references. The result is a timeline tailored to your specific location's frost window, not a generic national average.

Why Your Last Frost Date Is the Key to the Whole Season

Every date on your growing timeline is calculated relative to one anchor: your average last spring frost date. This is the date after which ground-level temperatures are unlikely to drop below 0 °C (32 °F) and tender plants can safely be moved outside.

In the UK, the last frost date ranges from late February on the Cornish coast to late May in the Scottish Highlands. In the US, it ranges from January in Florida to June in Montana. Getting this date right — even roughly — is the single most impactful thing you can do for your planning.

You can find your approximate last frost date from your national weather service, or use a local gardening society's historic averages. When in doubt, use a date one to two weeks later than you think — it is always safer to transplant a slightly mature seedling than to risk a late frost.

Common last frost dates by region

Cornwall, UKLate Feb – Early Mar
London, UKLate Mar – Early Apr
Midlands, UKMid Apr
Scotland, UKMid–Late May
Southern US (Zone 9)Feb – Early Mar
Mid-Atlantic US (Zone 6)Mid Apr – Mid May
Northern US (Zone 4)Mid May – Early Jun
Canada (Zone 5)Late May

How to Read Your Planting Schedule

S

Sow Indoors

Start seeds in trays or modules inside, typically 6–10 weeks before your frost date. This gives heat-loving crops (tomatoes, peppers, aubergines) time to establish before outdoor conditions are warm enough.

D

Direct Sow Outdoors

Hardy crops like carrots, peas and spinach can go straight into prepared ground. Timing varies — some go out weeks before the last frost, others need the soil to be reliably warm first.

T

Transplant Outdoors

Move indoor-started seedlings to their final position after the frost has passed and after a 7–10 day hardening-off period. Skipping hardening off is one of the most common reasons transplants fail.

H

First Harvest Expected

An estimate of when your crop should be ready to pick for the first time. Weather, soil health and variety will shift this by a week or two in either direction. Use it as a target, not a guarantee.

Frequently Asked Questions

What is the last frost date and how do I find mine?

Your last frost date is the average calendar date on which night-time temperatures at ground level stop falling below freezing in spring. You can find yours by checking your national meteorological service (the Met Office in the UK, NOAA in the US), searching "last frost date [your town]" online, or asking at a local garden centre. Treat it as a probability, not a certainty — there is always some risk of a late frost, which is why hardening off matters.

Can I use this calculator if I grow in a greenhouse or polytunnel?

Yes — but adjust your effective frost date earlier. A polytunnel typically extends your season by 4–6 weeks, and a heated greenhouse removes frost risk entirely. If you grow under cover, enter a frost date 4 weeks earlier than your outdoor last frost date to generate an appropriate starting schedule.

Why does the calculator show sow dates that are in the past?

This happens when your last frost date has already passed this year, which means the sowing window for some crops is behind you. You have two options: sow now and accept a later harvest, or plan ahead for next season. Many gardeners use the tool in autumn and winter to prepare seed orders for the following year.

What is hardening off and why is it on my timeline?

Hardening off is the process of gradually acclimatising indoor-grown seedlings to outdoor conditions before transplanting. Start by placing them outside in a sheltered spot for 1–2 hours per day, increasing exposure over 7–10 days. Skipping this step causes transplant shock — wilting, leaf scorch or stunted growth — because seedlings grown inside are not adapted to wind, direct sun or temperature fluctuation.

How accurate are the harvest date estimates?

The estimates are based on typical days-to-maturity figures for each crop under average UK/temperate growing conditions. Real harvest dates depend on your local climate, soil quality, variety chosen, and whether it is a warm or cold season. Treat the harvest window as a 2–3 week range centred on the date shown. Keeping a growing journal for a season or two will help you calibrate these estimates for your specific plot.

Can I plan multiple crops at once?

Currently the tool generates one timeline per crop. To plan a full kitchen garden, run the calculator for each crop in turn and note the key dates. For a more integrated approach — where you can see all your crops, beds and tasks in one place — EdenVatika's free planner app lets you build and track full planting schedules across multiple raised beds.

Popular Crops: Key Timing at a Glance

The table below shows approximate sowing and harvest windows relative to a mid-April last frost date. Use the calculator above to generate exact dates for your location.

Crop Sow Indoors Transplant / Direct Sow First Harvest
🍅 Tomato Early Feb Late Apr Late Jul
🌶️ Pepper Late Jan Late Apr Early Aug
🥒 Cucumber Late Mar Late Apr Mid Jul
🥬 Courgette Late Mar Late Apr Early Jul
🥕 Carrot Direct sow Mid Apr Late Jun
🥦 Broccoli Late Jan Mid Apr Mid Jul
🌿 Basil Early Mar Late Apr Late Jun
🫛 Pea Direct sow Late Feb Late Jun
🥔 Potato Chit indoors Mid Mar Late Jul
🌻 Sunflower Late Mar Late Apr Late Aug

Based on a last frost date of 15 April. Dates shift by approximately one week for every week your frost date differs.

More Free Gardening Tools

Everything you need to plan, track and grow a productive kitchen garden.

EdenVatika App

This tool calculates one timeline.
The app saves them all — automatically.

Instead of re-entering your frost date every visit, the app stores your location, generates your personalised planting calendar for every crop, and reminds you exactly when to act.

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  • 🔔

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    Email alerts when it's time to sow, pot on or plant out (Pro)

  • 🔁

    Succession planting

    Plan multiple sowing rounds so harvests are spread over weeks (Pro)

  • 🖨️

    Print your calendar

    Export a printable PDF of your full planting schedule (Pro)

  • 🤖

    AI garden planner

    Get a full personalised growing plan based on your location and beds (Pro)

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