One of the most cheerful crops in the garden. Edible seeds and cut flowers. Direct sow only — sunflowers dislike transplanting. Great for attracting pollinators and beneficial insects.
Plant window opens
May 15
Last chance to plant
Jul 31
Last frost
~May 1
Days to harvest
70–100 days
Difficulty
Easy
Wrong season — Zone 4
Harvest: Aug – Sep
Planting Calendar
In Zone 4, Sunflower can be planted outdoors from May 15 — the window closes around Jul 31.
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
plant
too early
too early
too early
too early
plant
plant
plant
too late
too late
too late
too late
too late
harvest
harvest
harvest
harvest
too early
plant window
harvest
too late
Direct sow. Succession plant 3 weeks apart for extended bloom.
Flowering cropBest planted at full moon
Growing Journey
Here is what to expect at each stage — and what to do when you get there.
GerminationDay 5-14
Sow directly after last frost. Sunflowers grow fast and transplant poorly.
SeedlingDay 7-21
Protect from slugs and snails — they love young sunflower seedlings.
EstablishedDay 21-60
Stake tall varieties before they need it — sunflowers are vulnerable to wind damage before they are fully established.
FloweringDay 60-80
If growing for seeds, do not cut — leave on the plant to mature fully.
Seed HarvestDay 90-120
Cut the head with 12 inches of stem, hang upside down in a dry airy place, and cover with paper bag to catch seeds as th
What to Expect
Typical yield
200-2000 seeds per head depending on variety
Sunflowers are endlessly rewarding — fast, cheerful, and generous with their seeds.
Key factorsvariety sizebird protection at seed stagefull sun
Get notified when to plant, water, and harvest your Sunflower — personalized for your zone.
Grown Sunflower before?or
Care Guide
Sunlight
Full sun · 6–8 hrs/day
Watering
Low
Spacing
12–24 inches
Soil
Well-draining, moderate fertility
Days to maturity
70–100 days
Soil pH
6.0–7.5
Plant tip · Zone 4
Direct sow. Succession plant 3 weeks apart for extended bloom.
How to know it's ready
For seeds: harvest when back of head turns brown and seeds are plump — usually 30–45 days after flowering. For cutting: harvest when just 1–2 rows of petals are open, early morning.
Watering Sunflower
How often
Weekly — drought tolerant once established
How much
1 inch per week
Method
At soil level — avoid wetting flowers
Overwatering signs
Yellow lower leaves, root rot
Underwatering signs
Drooping heads, wilting
Feeding Schedule
How often
monthly
Feed type
Balanced fertilizer
Key timing
switch to high-potassium at bud formation
NPK: 10-10-10 — avoid high N which delays flowering
Feed balanced fertilizer monthly. Switch to low-nitrogen, high-potassium feed when buds form for better head development.
Example product: Espoma Garden-Tone
Reminder: every 28 days after feeding
Succession Planting
Sow every 2 weeks
Sow every 2 weeks from last frost through midsummer for a continuous display and staggered seed harvest. Each planting blooms for 2–3 weeks — a single sowing gives a brief moment. Succession turns that moment into months. For cut flowers, pick when petals are just opening. For edible seeds, wait until the back of the head turns yellow-brown and petals have dropped. A late sowing in midsummer will still produce fully before first frost in most zones.
Direct
Direct sow after last frost. Sunflowers are so fast-growing that indoor starting offers little advantage for most zones.
Ground or raised bed recommended
Best grown in the ground or a large raised bed.
Companion Planting
Some plants help Sunflower thrive. Others compete or cause problems.
Grows well with
CucumbersSquash
Keep apart from
PotatoesBeans
Common Problems
Something went wrong? Here is what likely happened and what to do differently next time.
Frost or cold damage
What happened: Cold or frost at a vulnerable moment — germination, seedling stage, or transplant — can set back or kill plants that are not yet established enough to handle it.
Next season: Know your last frost date and work from it. Cover vulnerable plants with fleece when frost threatens, especially in the first few weeks after planting out.
Pests or disease
What happened: Most pest and disease problems are manageable if caught early. Regular checking — especially undersides of leaves — is the most effective prevention.
Next season: Check plants weekly and act at the first sign of a problem. Remove affected material promptly. Healthy, well-fed plants in good conditions resist pests better than stressed ones.
Too much water
What happened: Overwatering is one of the most common causes of plant failure. Roots need oxygen as well as moisture — waterlogged soil suffocates them.
Next season: Water deeply but less often rather than a little every day. Most plants prefer to dry out slightly between waterings. Good drainage is as important as watering.
Too little water
What happened: Drought stress causes wilting, reduced production, and makes plants more susceptible to pest and disease. Stress at critical moments — germination, flowering, fruiting — causes the most damage.
Next season: Mulching around plants is the single most effective way to retain soil moisture and reduce watering frequency.
Not enough sun
What happened: Most vegetables and fruits need 6-8 hours of direct sun. In less light they grow slowly, produce poorly, and are more vulnerable to disease.
Next season: Observe your garden through the day and map where the sun falls at different times. Match crops to the light levels available — shade-tolerant crops for shaded spots, sun-lovers for the brightest beds.
Pests & Diseases
Know what to look for before it gets out of hand — early identification is the most important step.
Aphids
pestmedium
What to look for
Clusters of tiny soft insects on new growth and leaf undersides. Leaves curl, yellow, or become sticky with honeydew. Sooty black mold may follow.
Cause
Multiple aphid species. Populations explode rapidly in warm weather.
Organic treatment
Blast off with strong water jet. Apply insecticidal soap or neem oil directly to colonies. Introduce ladybugs or lacewings.
Prevention
Plant marigolds and nasturtiums nearby. Avoid excess nitrogen fertilizer which creates soft, aphid-attractive growth. Encourage beneficial insects.
Slugs & snails
pestmedium
What to look for
Irregular holes in leaves overnight. Slime trails visible in morning. Seedlings may be severed at soil level.
Cause
Slugs and snails. Active in cool, moist conditions and at night.
Organic treatment
Set out beer traps at soil level. Apply diatomaceous earth around plant bases. Hand-pick at night with a torch. Iron phosphate slug pellets are organic-approved.
Prevention
Reduce mulch depth near seedlings. Eliminate hiding spots. Encourage hedgehogs and ground beetles.
Powdery mildew
diseasemedium
What to look for
White powdery coating on leaf surfaces, stems, and sometimes fruit. Leaves may yellow and die. Worst in warm days with cool nights.
Cause
Fungal disease favoured by humid conditions with poor air circulation.
Organic treatment
Spray with diluted neem oil or a baking soda solution (1 tsp per quart water). Apply potassium bicarbonate spray. Remove and destroy affected leaves.
Prevention
Space plants for good airflow. Water at soil level, not on foliage. Choose resistant varieties. Avoid overhead irrigation.
Recommended Varieties
Mammoth Russian (classic tall, huge seeds)
Lemon Queen (pale yellow, multi-branching)
Sunrich Gold (pollenless, for cutting)
Red Sun (dark red, unusual)
Dwarf Sunspot (compact, container)
Lemon Queen is the best for pollinators — multi-branching, produces dozens of flowers per plant over a long season.
Good to follow: Most crops — sunflowers are light-feeding and leave soil in good condition
Sunflowers have mild allelopathic effects on potatoes and some beans. Otherwise broadly compatible and beneficial anywhere.
Storing Your Harvest
Room temp
7–10 days in water as cut flower. Seeds: months in cool dry place
Fridge
N/A for cut flowers
Freezer
Seeds: freeze for longer storage
Cut when 1–2 outer petals have opened. For seeds: dry the head fully on the plant, then hang in paper bag to finish drying.
Free app · Kickstarter October 2027 · iOS February 2028
Know exactly when to plant, prune, and harvest Sunflower
plant uses your ZIP code and real frost data to tell you the right day — not just the right month. Get notified when your planting window opens, when to succession sow, and when to cut back for next season.
You're in ✓ — we'll be in touch before launch.
Something went wrong — try again.
Be first to back on Kickstarter · founding grower pricing locked in.
Common questions
In Zone 4, direct sow sunflower outdoors May 20 – Jun 10 after your last frost of approximately May 1. Direct sow. Succession plant 3 weeks apart for extended bloom.
Zone 4 has an average last spring frost around May 1 and a first fall frost around Oct 1. These vary by location — the plant app uses your ZIP code with NOAA data for precision.
Good companions for sunflower include Cucumbers, Squash. Avoid planting near Potatoes, Beans.
Sunflower typically takes 70–100 days to harvest in Zone 4. Expected harvest window: Aug – Sep.
These guides get better when growers share what they know. If something's off or you've learned something worth passing on, add it here -- accepted tips earn you a Founding Grower badge when plant launches.
Your tip for growing Sunflower
Your name (optional)
Your zone
Your email (optional)
Tips are reviewed before publishing. Zone 4 tips appear on nearby zone pages too.
Thanks for sharing. We read every tip before anything goes live -- if yours makes it onto the page, you'll hear from us before the app launches. Good growing.
What needs correcting?
What should it say?
Your email (optional)
Got it -- we take data accuracy seriously around here. We'll review this against our sources and update the guide if needed. Thanks for keeping us honest.