Planting Calendar Planner

Season Plan

Start {{ startDateDisplay }} Transplant {{ transplantDateDisplay }} Harvest {{ harvestWindowDisplay }} Successions {{ successionCountDisplay }} Season {{ seasonLengthDisplay }} Buffer {{ frostBufferDisplay }} Prep {{ bedPrepLeadDisplay }} Gap {{ successionIntervalBadge }} {{ zoneLabel }}

Last spring frost:

First fall frost:

USDA zone:

Crop preset:

Harvest goal:

Days to maturity:

days

Transplant lead:

weeks

Season extension:

weeks

Hardening days:

days

Direct sow:

Successions:

cycles

Notes seed:

Bed prep lead:

days

Succession override:

days

Milestone	Date	Copy
{{ milestone.label }}	{{ milestone.value }}

Date	Phase	Batch	Notes	Copy
{{ item.date }}	{{ item.phase }}	{{ item.batch }}	{{ item.notes }}

Season insights

{{ insight }}

No insights yet—enter frost dates and crop details to generate analysis.

Timeline uses day offsets from the seed-start date. Harvest window trims to first fall frost minus buffer days.

Add your frost dates and crop choice to build a sowing and harvest calendar.

Tags: Education , Gardening , Productivity

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Planting calendars turn local frost dates and crop needs into a season plan that shows when to start seeds, move plants outside, and begin harvest. They help align labor and bed space so yield arrives when your kitchen or pantry is ready. A clear succession planting schedule reduces guesswork in busy weeks.

Enter your average last spring frost and, if you know it, your first fall frost. Choose a crop and its maturity time, then decide whether to start indoors or sow direct so the plan matches your beds and tools. Results organize the work into simple phases you can copy to lists or reminders.

You might, for example, plan tomatoes after a mid April frost and see seed trays start in early March with harvest beginning in early July and tapering in September. The same approach works for quick greens where shorter maturity and tighter gaps keep salads coming.

Treat dates as planning anchors rather than promises because weather and microclimates can shift growth by a few days. Improve reliability by using local records, keeping units consistent, and reviewing notes after each season.

Technical Details:

The core quantities are the frost‑free window between your last spring frost and first fall frost, the crop’s days to maturity, and any protection that extends either end. From these, the planner computes a field date for transplanting or direct sowing, then derives indoor seed starting and hardening periods when applicable.

The harvest window opens after the maturity period and closes at the earlier of a preset harvest duration or a cap tied to the first fall frost with a zone‑based buffer and any protection. Reported metrics include frost window days, crop span, harvest buffer, and the realized succession count.

Succession spacing follows a crop default cadence and adapts to your goal. Fresh table aims for steady picking with shorter gaps, preserving aims for one larger flush with wider gaps, and a custom override sets a fixed day interval with a minimum of five days.

Comparisons make sense when you hold location and season settings constant. Read outputs as a plan that absorbs normal variation rather than a guarantee for a particular cultivar or microclimate.

\begin{array}{l} e = round (7 \times w) \\ b = {7 if frost‑sensitive, else 3} \\ s = min (b, e) \\ t_trans = t_last + {max(0, 3 − min(e, 3)) if direct sow, b − s if transplant} \\ t_harden = t_trans - h \\ t_seed = t_harden - 7 \times ℓ \\ t_open = t_trans + D \\ t_default = t_open + max (14, H) \\ t_cap = t_first + min (e, 21) - p \\ t_end = if first frost set : min (t_default, t_cap) else t_default \\ S = diffDays (t_last, t_first) \\ G = diffDays (t_trans, t_end) \\ B = diffDays (t_first, t_end) \end{array}

Symbols and units
Symbol	Meaning	Unit/Datatype	Source
t_last	Last spring frost date	YYYY‑MM‑DD	Input
t_first	First fall frost date (optional)	YYYY‑MM‑DD	Input
D	Days to maturity	days	Input or preset
ℓ	Transplant lead	weeks	Input or preset
h	Hardening period	days	Input
w	Season extension	weeks	Input
e	Extension converted	days	Derived
b	Base frost buffer	days	Preset
p	Zone harvest padding	days	Zone map
t_trans	Transplant or direct‑sow date	YYYY‑MM‑DD	Derived
t_seed	Indoor seed start date	YYYY‑MM‑DD	Derived
t_open	Harvest window opens	YYYY‑MM‑DD	Derived
t_end	Harvest window ends	YYYY‑MM‑DD	Derived
S	Frost‑free window	days	Derived
G	Crop span in field	days	Derived
B	Buffer before frost	days	Derived

Worked example. Inputs: last frost 2025‑04‑20, first frost 2025‑10‑05, zone 6, tomato preset, D=75, ℓ=6, h=7, w=2, direct sow off, successions=3.

\begin{array}{l} e = 14 \\ b = 7 \\ s = 7 \\ t \end{array}

_trans=2025‑04‑20 t_harden=2025‑04‑13 t_seed=2025‑03‑02 t_open=2025‑07‑04 t_end=2025‑09‑12 S=168 days G=145 days B=23 days

Interpretation: transplant on 2025‑04‑20, harvest from 2025‑07‑04 to 2025‑09‑12, buffer 23 days before the first fall frost, three successions spaced 28 days.

Zone harvest padding map
Zone	Harvest padding (days)
3	21
4	18
5	14
6	10
7	7
8	5
9	3
10	2
11	0

Crop presets
Preset	Days to maturity	Lead (weeks)	Succession gap (days)	Frost sensitive	Direct sow default	Harvest window (days)
Tomato (indeterminate)	75	6	28	Yes	No	70
Pepper (sweet)	80	8	32	Yes	No	60
Lettuce (butterhead)	55	3	14	No	No	28
Bush bean	58	0	18	Yes	Yes	35
Kale	60	4	30	No	No	90
Carrot	70	0	21	No	Yes	45

Units, precision, and rounding:

Dates use the ISO order year‑month‑day. All durations are whole days. Day differences are rounded to the nearest day using UTC to avoid daylight‑saving drift. Chart bars enforce a minimum one‑day duration for legibility.

Validation and bounds:

Inputs and constraints
Field	Type	Min	Max	Step/Pattern	Error text	Placeholder
Last spring frost	Date	—	—	YYYY‑MM‑DD	Last spring frost date must be YYYY‑MM‑DD.	—
First fall frost	Date (optional)	—	—	YYYY‑MM‑DD	Must be after the last spring frost.	—
Zone	Select	3	11	—	—	—
Days to maturity	Number	25	180	1	Clamped to range.	70
Transplant lead	Number	0	16	0.5	Clamped to range.	6
Hardening days	Number	0	14	1	Clamped to range.	7
Season extension	Number	0	6	0.5	Clamped to range.	2
Direct sow	Switch	—	—	boolean	—	—
Successions	Number	1	6	1	Clamped to range.	3
Bed prep lead	Number	0	21	1	Clamped to range.	5
Succession override	Number	0	60	1	Uses ≥ 5 when set.	24
Notes seed	Text	—	32 chars	—	—	zone6b‑backyard

I/O formats:

I/O summary
Input	Accepted families	Output	Encoding/Precision	Rounding
Dates, numbers, toggles	Calendar dates, integers, decimals	Milestones, schedule, timeline, JSON	Dates as YYYY‑MM‑DD, whole days	Nearest day (UTC)

Randomness, seeds, and reproducibility:

A deterministic seeded generator produces advisory tips so repeated inputs yield the same note. Randomness does not affect computed dates. You can provide a seed string to keep phrasing stable across runs.

Networking & storage behavior:

All computations and file exports occur on your device. Clipboard operations require permission. No data is transmitted or stored server‑side.

Assumptions & limitations:

Frost dates represent long‑term averages; single seasons vary.
Zone padding trims harvest near the first fall frost; it is not a weather forecast.
Days to maturity are packet averages; cultivar and soil conditions shift timing.
Succession gaps are fixed by rule or override; they do not react to yield feedback.
Season extension shortens early buffers and can extend the fall cap within limits.
Without a fall frost date, the harvest window uses the preset duration only.
Chart bars are schematic; durations are rounded for readability.
Heads‑up Valid patterns do not guarantee yield; use test patches when trying new varieties.

Edge cases & error sources:

Invalid date strings cause an error and halt computation.
A fall frost before the last spring frost is rejected.
Out‑of‑range numbers are clamped to defined bounds.
Very long maturity may push harvest close to or past the fall cap.
High succession counts may be trimmed if dates exceed the harvest end.
Zero hardening days removes that phase but keeps other milestones.
Direct sow changes early offsets and removes seed‑start and hardening phases.
Custom succession override below five is raised to five days.
Large bed‑prep leads add earlier tasks but do not alter field dates.
Rounding uses UTC midnights; entries set near leap‑day transitions remain whole‑day accurate.

Privacy & compliance:

No personal data is transmitted or stored server‑side. Exports are generated locally. Avoid entering sensitive information into notes.

Step‑by‑Step Guide:

Plan a crop calendar that converts frost dates and maturity into actionable field dates.

Enter Last spring frost and, if known, First fall frost.
Select your hardiness zone and choose a crop preset or set custom maturity and lead.
Decide on Direct sow or transplant with hardening days.
Pick a harvest goal; add successions and, if needed, a custom interval.
Optionally add a bed‑prep lead to schedule prep ahead of each field date.
Review milestones and schedule, then export or copy what you need.

Example: Zone 6 tomatoes with last frost 2025‑04‑20, maturity 75 days, lead 6 weeks, hardening 7 days → seed 2025‑03‑02, transplant 2025‑04‑20, harvest opens 2025‑07‑04.

You now have a clean sequence of dates ready for your season plan.

FAQ:

Is my data stored?

No. Everything runs on your device, and exports or clipboard actions occur locally. Nothing is sent to a server.

Clipboard permissions may prompt once per session.

How accurate is the schedule?

It reflects averages plus a zone buffer and any protection. Expect shifts of a few days from weather and site effects. Use notes to refine next season.

What units and formats are used?

Dates use YYYY‑MM‑DD. Durations are days. Calculations use UTC to keep day counts stable.

Can I work without a connection?

Yes. After the page loads, planning and exports continue to work without network access.

How do I plan tomatoes in zone 6?

Select the tomato preset, set zone 6 and your frost dates, keep the default 6‑week lead and 75‑day maturity, then review the three successions at 28‑day gaps.

What does a “buffer 0 days” result mean?

Harvest ends on the first fall frost date. Keep protection ready or reduce succession spacing to finish earlier.

How do I export my plan?

Use the milestone or schedule actions to copy CSV or download CSV and DOCX summaries. A JSON view is also available for records.

Does a custom succession override the goal?

Yes. A set interval replaces goal‑based cadence, with a minimum of five days between field dates.

Glossary:

Days to maturity (DTM): Average days from transplant or emergence to first harvest.
Hardening off: Gradual outdoor acclimation of seedlings before transplant.
Season extension: Protection that adds days at the edges of the season.
Succession planting: Staggered plantings to smooth harvest over time.
Frost‑free window: Days between last spring frost and first fall frost.
Harvest buffer: Days remaining between the last planned harvest and first fall frost.

Planting Calendar Planner

Season Plan

Season insights

Introduction:

Technical Details:

Units, precision, and rounding:

Validation and bounds:

I/O formats:

Randomness, seeds, and reproducibility:

Networking & storage behavior:

Assumptions & limitations:

Edge cases & error sources:

Privacy & compliance:

Step‑by‑Step Guide:

FAQ:

Glossary: