Learn/ Charts

Garden charts & quick reference

The tables growers actually keep taped inside the shed door — zones and frost dates, companions, seed-starting math, spacing, pH, compost ratios, and rotation families. Set your zone once and the date charts recalculate.

Your USDA zone

Average last frost: 04-25 · first frost: 10-15

Zone 6b — winter lows around -5 to 0 °F.

Zone & frost lesson

USDA hardiness zones & frost dates

Averages — check a local extension office for microclimate adjustments.

Zone	Winter low	Last frost	First frost	Frost-free days	What that means
3a	-40 to -35 °F	05-30	09-10	103 days	Short season — start most warm crops indoors, use row cover.
3b	-35 to -30 °F	05-25	09-15	113 days	Short season — start most warm crops indoors, use row cover.
4a	-30 to -25 °F	05-20	09-20	123 days	Short season — start most warm crops indoors, use row cover.
4b	-25 to -20 °F	05-15	09-25	133 days	Short season — start most warm crops indoors, use row cover.
5a	-20 to -15 °F	05-10	10-01	144 days	Classic four-season garden — one main summer crop, fall greens.
5b	-15 to -10 °F	05-05	10-05	153 days	Classic four-season garden — one main summer crop, fall greens.
6a	-10 to -5 °F	04-30	10-10	163 days	Classic four-season garden — one main summer crop, fall greens.
6b	-5 to 0 °F	04-25	10-15	173 days	Classic four-season garden — one main summer crop, fall greens.
7a	0 to 5 °F	04-15	10-25	193 days	Long season — spring and fall plantings both fit comfortably.
7b	5 to 10 °F	04-05	11-05	214 days	Long season — spring and fall plantings both fit comfortably.
8a	10 to 15 °F	03-30	11-15	230 days	Long season — spring and fall plantings both fit comfortably.
8b	15 to 20 °F	03-20	11-25	250 days	Long season — spring and fall plantings both fit comfortably.
9a	20 to 25 °F	02-28	12-05	280 days	Near year-round growing; summer heat is the limiting factor.
9b	25 to 30 °F	02-15	12-15	303 days	Near year-round growing; summer heat is the limiting factor.
10a	30 to 35 °F	01-30	12-25	329 days	Frost-free — grow cool crops in winter, heat-tolerant in summer.
10b	35 to 40 °F	01-15	12-30	349 days	Frost-free — grow cool crops in winter, heat-tolerant in summer.
11a	40 to 45 °F	01-01	12-31	364 days	Frost-free — grow cool crops in winter, heat-tolerant in summer.
11b	45 to 50 °F	01-01	12-31	364 days	Frost-free — grow cool crops in winter, heat-tolerant in summer.

Companion planting chart

Grow-with pairings support pollination, pest confusion, or shade. Keep-apart pairings compete or share disease.

Crop	Plant with	Keep apart	Why it matters
Tomato	BasilMarigoldCarrotOnion	BrassicasFennelCorn	Hornworm, aphids, blight. Rotate 3-year cycle to break disease.
Pepper	BasilOnionCarrot	BeansFennel	Aphids, flea beetles. Row cover early season.
Lettuce	RadishCarrotOnionStrawberry	Broccoli (competes for water)	Slugs, aphids. Water in the morning.
Carrot	OnionRosemaryLettuceTomato	Dill	Carrot rust fly. Row cover; avoid disturbing tops.
Bush bean	CornCucumberCarrotSquash	OnionGarlic	Mexican bean beetle. Handpick early.
Cucumber	BeanCornRadishDill	SageMelons (share pests)	Cucumber beetle, squash bug. Row cover until flowering.
Zucchini	NasturtiumCornBean	Potato	Squash vine borer. Wrap stem base in foil early.
Kale	OnionBeetHerbs	TomatoStrawberry	Cabbage worm. Row cover or Bt spray.
Spinach	StrawberryRadish	No known conflicts	Leaf miner. Row cover.
Beet	OnionLettuceBrassicas	Pole bean	Leaf miner.
Radish	CarrotLettuceCucumber	Hyssop	Flea beetle.
Onion	CarrotBeetLettuceTomato	BeanPea	Thrips.
Garlic	TomatoCabbageBeet	BeanPea	Few — a garden protector.
Potato	BeanCornMarigold	TomatoCucumber	Colorado potato beetle. Handpick daily.
Broccoli	OnionBeetHerbs	TomatoStrawberry	Cabbage worm, aphid. Row cover.
Basil	TomatoPepper	No known conflicts	Japanese beetle.
Sweet corn	BeanSquashCucumber	Tomato	Corn earworm. A drop of mineral oil on the silks after pollination helps.
Strawberry	SpinachLettuceOnion	Brassicas	Slugs, birds. Straw mulch + netting.
Winter squash	CornBeanNasturtium	Potato	Squash bug, vine borer.
Pea	CarrotRadishCucumber	OnionGarlic	Aphid, pea moth.
Cilantro	SpinachBeanTomato	Fennel	Aphids. Bolts fast in heat — sow in shoulder seasons.
Parsley	TomatoAsparagusCarrot	MintLettuce	Swallowtail caterpillars (leave them — the butterflies are worth it).
Chives	CarrotTomatoAppleStrawberry	BeanPea	Rarely bothered — repels aphids and Japanese beetles nearby.
Mint	CabbageTomato	Everything perennial nearby — it takes over	None serious; deters cabbage moths and ants.
Oregano	PepperTomatoBasil	No known conflicts	Rarely bothered.
Thyme	CabbageStrawberryEggplant	No known conflicts	Deters cabbage worms.
Rosemary	CarrotBeanCabbage	No known conflicts	Rarely bothered.
Sage	RosemaryCabbageCarrot	CucumberOnion	Deters cabbage moths and carrot fly.
Dill	CabbageCucumberLettuceOnion	CarrotTomato	Attracts beneficial wasps — a garden ally.
Raspberry	GarlicChivesYarrow	PotatoTomatoBlackberry (shared disease)	Japanese beetle, spotted-wing drosophila, cane borer.
Blueberry	StrawberryRhododendron	Anything needing lime	Birds are the main threat — net at pinking.
Blackberry	BeanGarlic	RaspberryNightshades	Spotted-wing drosophila, cane borers.
Grape	BasilHyssopChives	CabbageRadish	Japanese beetle, birds, powdery mildew.
Fig	StrawberryRosemary	No known conflicts	Birds, wasps at ripening. Net or bag fruit.
Apple	ChivesNasturtiumGarlicComfrey	Potato	Codling moth, apple maggot. Bag fruit or use kaolin clay.
Pear	ChivesGarlicNasturtium	No known conflicts	Codling moth, pear psylla, fire blight — plant resistant varieties.
Peach	BasilChivesGarlic	No known conflicts	Peach leaf curl (spray dormant oil), oriental fruit moth, borers.
Watermelon	CornRadishNasturtium	CucumberPotato	Cucumber beetle, squash bug.
Cantaloupe / Melon	CornRadishBean	Potato	Cucumber beetle, aphid.
Rhubarb	CabbageBeanBroccoli	No known conflicts	Rarely bothered.

Seed-starting & planting-out calendar — Zone 6b

Dates recalculated from your zone's average last frost.

Crop	Start indoors	Method	Into the ground	Days to maturity
Tomato	2026-03-14	Transplant	2026-05-09	60-85 days
Pepper	2026-02-28	Transplant	2026-05-09	60-90 days
Lettuce	2026-03-28	Transplant	2026-04-11	30-60 days
Carrot	—	Direct sow	2026-04-04	60-80 days
Bush bean	—	Direct sow	2026-05-02	50-65 days
Cucumber	2026-04-04	Transplant	2026-05-09	50-70 days
Zucchini	2026-04-04	Transplant	2026-05-09	45-55 days
Kale	2026-03-14	Transplant	2026-04-04	50-65 days
Spinach	—	Direct sow	2026-03-28	35-45 days
Beet	—	Direct sow	2026-04-04	50-70 days
Radish	—	Direct sow	2026-03-28	22-30 days
Onion	2026-02-14	Transplant	2026-04-11	90-120 days
Potato	—	Direct sow	2026-04-11	70-120 days
Broccoli	2026-03-14	Transplant	2026-04-04	60-90 days
Basil	2026-03-14	Transplant	2026-05-09	60 days
Sweet corn	—	Direct sow	2026-05-09	65-90 days
Winter squash	2026-04-04	Transplant	2026-05-09	80-110 days
Pea	—	Direct sow	2026-03-21	55-70 days
Cilantro	—	Direct sow	2026-04-11	45-70 days
Parsley	2026-02-28	Transplant	2026-04-11	70-90 days
Chives	2026-02-28	Transplant	2026-04-04	80-90 days (perennial)
Oregano	2026-02-28	Transplant	2026-05-09	80-90 days (perennial)
Thyme	2026-02-28	Transplant	2026-05-09	75-90 days (perennial)
Rosemary	2026-02-14	Transplant	2026-05-09	1st-year harvest (perennial in zone 7+)
Sage	2026-02-28	Transplant	2026-05-09	75 days (perennial)
Dill	—	Direct sow	2026-04-25	40-60 days
Watermelon	2026-04-04	Transplant	2026-05-09	70-100 days
Cantaloupe / Melon	2026-04-04	Transplant	2026-05-09	70-90 days

Spacing, sun & seed depth

Spacing is in-row for intensive beds; add 6–12 in between rows for walking paths.

Crop	Sun	Spacing	Seed depth	Min. container
Tomato	Full sun, 8+ hrs	24-36 in	¾–1 in	5–7 gal
Pepper	Full sun	18 in	¾–1 in	5–7 gal
Lettuce	Full sun to part shade	8-12 in	½ in	3 gal
Carrot	Full sun	2-3 in	¼ in	1 gal / window box
Bush bean	Full sun	4-6 in	¼ in	1 gal / window box
Cucumber	Full sun	12 in (trellis)	½ in	3 gal
Zucchini	Full sun	24-36 in	¾–1 in	5–7 gal
Kale	Full sun to part shade	18 in	¾–1 in	5–7 gal
Spinach	Part shade in summer	4-6 in	¼ in	1 gal / window box
Beet	Full sun	3-4 in	¼ in	1 gal / window box
Radish	Full sun	1-2 in	¼ in	1 gal / window box
Onion	Full sun	4-6 in	¼ in	1 gal / window box
Garlic	Full sun	4-6 in	¼ in	1 gal / window box
Potato	Full sun	12 in	½ in	3 gal
Broccoli	Full sun	18-24 in	¾–1 in	5–7 gal
Basil	Full sun	12 in	½ in	3 gal
Sweet corn	Full sun	12 in (block plant)	½ in	3 gal
Strawberry	Full sun	12 in	½ in	3 gal
Winter squash	Full sun	36-48 in	1–1½ in	10–20 gal
Pea	Full sun to part shade	2-4 in	¼ in	1 gal / window box
Cilantro	Full sun to part shade	6-8 in	¼ in	1 gal / window box
Parsley	Full sun to part shade	8-10 in	½ in	3 gal
Chives	Full sun to part shade	6-8 in	¼ in	1 gal / window box
Mint	Part shade to full sun	18-24 in (contain!)	¾–1 in	5–7 gal
Oregano	Full sun	12-18 in	½ in	3 gal
Thyme	Full sun	10-12 in	½ in	3 gal
Rosemary	Full sun	24-36 in	¾–1 in	5–7 gal
Sage	Full sun	18-24 in	¾–1 in	5–7 gal
Dill	Full sun	10-12 in	½ in	3 gal
Raspberry	Full sun	24-36 in in rows 6 ft apart	¾–1 in	5–7 gal
Blueberry	Full sun	4-6 ft	¼ in	1 gal / window box
Blackberry	Full sun	3-4 ft in rows 8 ft apart	¼ in	1 gal / window box
Grape	Full sun, 8+ hrs	6-8 ft on a trellis	¼ in	1 gal / window box
Fig	Full sun	10-15 ft (tree)	½ in	3 gal
Apple	Full sun	10-15 ft (semi-dwarf)	½ in	3 gal
Pear	Full sun	12-20 ft (standard)	½ in	3 gal
Peach	Full sun	12-15 ft (semi-dwarf)	½ in	3 gal
Watermelon	Full sun, 8+ hrs	36-72 in on a mound	1–1½ in	10–20 gal
Cantaloupe / Melon	Full sun	24-36 in on a mound	¾–1 in	5–7 gal
Rhubarb	Full sun to part shade	36-48 in	1–1½ in	10–20 gal

Crop rotation by plant family

Rotate each family to a new bed for 3 years. Same-family repeats concentrate soil disease and family-specific pests.

Lamiaceae

Year 1 bed

Basil, Mint, Oregano, Thyme, Rosemary, Sage

Feeds moderately — follow with a legume or cover crop.

Rosaceae

Year 2 bed

Strawberry, Raspberry, Blackberry, Apple, Pear, Peach

Feeds moderately — follow with a legume or cover crop.

Cucurbitaceae

Year 3 bed

Cucumber, Zucchini, Winter squash, Watermelon, Cantaloupe / Melon

Heavy feeders and sprawlers. Follow with a legume or a cover crop.

Apiaceae

Year 4 bed

Carrot, Cilantro, Parsley, Dill

Light feeders with deep taproots that break compaction.

Solanaceae

Year 1 bed

Tomato, Pepper, Potato

Heavy feeders. Never follow themselves — blight and verticillium persist in soil for years.

Brassicaceae

Year 2 bed

Kale, Radish, Broccoli

Heavy nitrogen users. Rotate hard to break clubroot and cabbage root maggot cycles.

Amaryllidaceae

Year 3 bed

Onion, Garlic, Chives

Light feeders. Good gap-fillers between heavy-feeder years.

Fabaceae

Year 4 bed

Bush bean, Pea

Nitrogen fixers. Plant these after heavy feeders to rebuild the bed.

Amaranthaceae

Year 1 bed

Spinach, Beet

Moderate feeders; sensitive to acid soil, keep pH above 6.0.

Asteraceae

Year 2 bed

Lettuce

Light feeders, quick turnaround — fits anywhere in the rotation.

Poaceae

Year 3 bed

Sweet corn

Very heavy nitrogen feeder. Always follow with legumes.

Ericaceae

Year 4 bed

Blueberry

Feeds moderately — follow with a legume or cover crop.

Vitaceae

Year 1 bed

Grape

Feeds moderately — follow with a legume or cover crop.

Moraceae

Year 2 bed

Fig

Feeds moderately — follow with a legume or cover crop.

Polygonaceae

Year 3 bed

Rhubarb

Feeds moderately — follow with a legume or cover crop.

Soil pH targets

Most nutrients are most available between 6.0 and 7.0. Sulfur lowers pH; lime raises it — retest 3 months after amending.

Crop group	Target pH	Notes
Blueberry, cranberry	4.5–5.5	True acid lovers — amend with elemental sulfur and pine fines.
Potato	5.0–6.0	Low pH suppresses scab. Do not lime potato beds.
Tomato, pepper, eggplant	6.0–6.8	Calcium uptake fails below 5.8 — blossom end rot follows.
Beans, peas, squash, corn	6.0–7.0	Broad tolerance; nodulation drops sharply under 5.5.
Brassicas (kale, broccoli, cabbage)	6.5–7.5	Higher pH suppresses clubroot.
Most herbs (rosemary, thyme, sage)	6.0–7.5	Mediterranean herbs prefer lean, sharply drained soil.

Compost carbon-to-nitrogen ratios

Aim for an overall pile near 30:1 — roughly 2–3 parts browns by volume to 1 part greens.

Material	C:N ratio	Type
Dry leaves	60:1	Brown
Straw	80:1	Brown
Cardboard / paper	350:1	Brown
Wood chips / sawdust	400:1	Brown — slow, use sparingly
Vegetable scraps	20:1	Green
Coffee grounds	20:1	Green
Fresh grass clippings	15:1	Green
Manure (cow, horse)	20:1	Green — hot compost before use
Chicken manure	7:1	Green — very hot, age 6 months

Watering & irrigation guide

One inch of water per week ≈ 0.62 gallons per square foot. Water deeply and less often to drive roots down.

Situation	Water needed	How to deliver
Established in-ground bed	1 in/week	One deep soak; two in heat above 90°F.
Newly seeded row	Keep top ½ in damp	Light mist 1–2× daily until germination.
Fresh transplants (first 2 weeks)	Every 1–2 days	Water at the base, not the leaves.
Container, under 5 gal	Daily, often twice in heat	Water until it runs out the drain holes.
Container, 10–20 gal	Every 1–2 days	Mulch the surface to cut evaporation by ~25%.
Drip line, 1/2 in @ 0.5 gph	~45 min per inch	Emitters 12 in apart along the row.
Mulched bed	~30% less	2–3 in of straw or leaf mulch, kept off stems.

Succession sowing intervals

Sow the next round on the interval below to keep a steady supply instead of one giant glut.

Crop	Sow every	Stop sowing
Lettuce & salad mix	10–14 days	4 weeks before first frost
Radish	10 days	3 weeks before first frost
Bush beans	2–3 weeks	10 weeks before first frost
Carrots	3 weeks	10 weeks before first frost
Cilantro & dill	3 weeks	Continue into fall — bolts in heat
Spinach & arugula	2 weeks	Resume in fall; skip midsummer
Basil	4 weeks	8 weeks before first frost

Put these charts to work

Charts tell you what's possible. The planner and schedule turn them into dated tasks for your actual beds.

Open the toolkit Crop profiles