Helianthus annuus

Introduction: The sunflower is native to North America and was long grown by Native Americans, but first became an important commercial crop in Russia. This occurred after breeders produced a variety with unusually large, oil rich, seeds. Their use quickly spread throughout eastern Europe until they were the most important oil seed crop grown there. It is now an important crop in its native land as well, though even today many varieties are of Russian origin.

Many people think of sunflowers as an ornamental, rather than an edible crop, but the seeds are highly nutritious.

Crop use: The sunflower is valuable as a source of high protein seeds, but it could also be important as a garden scale source of oil (fats can be hard to grow in the garden). It is also very pretty (spectacular even) and provides food for beneficial insects.

Ease of growing: This is a pretty easy crop to grow if it has fertile soil, plenty of water and warm weather. It is rarely bothered by pests up until the seed starts to ripen (then birds and squirrels can be a problem).

Climate: Sunflowers like warm, humid growing conditions, similar to those for corn.

Nutritional content: Sunflower seeds contain about 20% protein, 20% carbohydrate, 40% fat (which is very rich in essential fatty acids), several B vitamins A, calcium, iron potassium and zinc.

With all of that fat and protein it should come as no surprise that the seeds contain over 2500 calories per pound.

About Sunflower  
Germination temp: 70 – 85°F
Germination time: 7 – 14 days
Seed viability: 3 – 5 years
Hardiness: Tender
Growing temp: 50 (60 – 75) 95˚F
Plant out: 2 weeks after last frost
Yield: 3 lb / 100 sq ft.
Days to harvest: 90  


pH: 6.0 to 7.0

Sunflowers are very hungry plants and for good growth they need rich moist soil with an abundance of nutrients. They like phosphorus and potassium, but not too much nitrogen as this may encourage leaf growth rather than flowering.

Soil preparation: Sunflowers are hungry crops, so enrich the soil generously before planting. Incorporate 3˝ of compost or aged manure, along with wood ashes, colloidal phosphate and kelp powder (or an organic fertilizer mix).


When: You can start planting sunflowers 2 weeks after the last frost date, when the soil has warmed up to at least 50°F.

Rotation: Sunflowers have a reputation for exhausting the soil if continually planted and harvested on the same piece of land. Always leave at least 3 years between crops.


Indoors: Sunflower are often started indoors for an early and protected start. The seedlings grow rapidly, so are best started in 4˝ pots (to give them plenty of room). Plant 2 – 4 seeds in each pot and when all have germinated you can thin to the best one (or two).

Outdoors: Sunflower seeds germinate and grow so rapidly they are usually direct sown. Plant them ¼˝ deep and keep moist and they will germinate and grow rapidly.

Spacing: Space the plants 12 – 24˝ apart, depending upon the variety.


Weeds: The young seedlings can’t compete with weeds very well, so weed them carefully. Once they get going they will soon outgrow any weeds.

Water: Sunflowers are thirsty plants and for maximum production they need a constant supply of water.

Mulch: In hot climates a mulch is useful to conserve soil moisture and  keep down weeds.

Pests and disease: Birds love sunflower seeds and can be a major pest in some areas. Squirrels and raccoons may also develop a taste for them and become a problem.


When: When the seeds are ripe the whole head will start to droop and the seeds will be fat and plump. Open a few seeds and see (and taste) if they are fully ripe. Watch carefully or birds will get the seed before you do.

How: The easiest way to harvest the seeds is to cut off the whole heads. Dry them in the sun and then rub the heads against a screen (or against each other) to free the seeds.

Storage: The seeds must be dried carefully if you want to store them for any length of time, otherwise they will mold. Store the dry seeds in a cool, rodent-free place.

Unusual growing ideas

Sunflower lettuce: Sunflower seeds can be grown indoors as a seedling salad crop. Soak the seeds for 3 hours and then spread them out, one seed deep, on trays of soil, peat moss or wet kitchen paper. Keep them in a warm place and mist daily. When the seeds begin to germinate move them into full light. The greens will be ready in 1 – 3 weeks (depending upon the temperature). Cut the plants with scissors when they are 3 – 6˝ tall, leaving about an inch of stem behind. See Microgreens for more on this.

Smother crop: Their luxuriant and rapid growth makes sunflowers useful as a smother crop. A dense stand of the tall plants will crowd out and eradicate persistent weeds.

Canary plant: Sunflowers are very sensitive to low soil moisture and can be used as indicator plants for the whole garden. Watch your sunflowers and when they wilt it means soil moisture is low and it is time to water the garden.

Temporary screen: These tall growing flowers can be used to make a quick (and pretty) temporary screen. If you feel ambitious you could try growing a sunflower maze.

Fertilizer: Sunflowers use four carbon photosynthesis which makes them more efficient when growing under high heat and light intensities. This means they can grow very quickly and produce an abundance of organic matter.

They are sometimes grown as a green manure crop, which is incorporated just before the flower buds appear (which is when the plants start to turn woody). They can also be grown to produce organic matter for the compost pile. If you want to try this its cheaper to use bulk raw seeds from a whole food store.

Apparently even their hunger for nutrients has been put to use. The plants have been used to remove an excess of nitrates from the soil.

Seed saving: Sunflowers are cross-pollinated by insects, so you can only save the seed from one variety at a time (they may also cross with any wild sunflowers).

Saving the seed is pretty easy, except for the fact that birds and squirrels may take every full kernel if you don’t protect them.


There are lots or ornamental sunflower varieties, but most don’t have large enough seeds to be very useful for food. The best edible seeded varieties include:

Skyscraper – As you might imagine it is tall, with huge seed heads (75 days)

Mammoth Russian – The classic heirloom sunflower (80 days).

Snack Seed – Big fat seeds.

Kitchen use

The raw or roasted kernels can be used like nuts: eaten out of hand, in baked goods, granola and trail mix. Native Americans often ground the whole seed to meal for baking bread and thickening soups.

Edible oil: Modern varieties of seed may contain up to 60% oil. This can be extracted by pressing the crushed seeds using a hand press such as the Piteba. You can also do as Native Americans used to do, boil the kernels in water and skim off the edible oil that floats to the surface.

Sprouts: The raw whole seed can be sprouted for salad greens (see Sprouting seeds). Don’t let the sprouts get too big or they may develop an acrid taste.

Eating sunflower seeds  

If you are to grow sunflowers for their edible seeds, you might want to learn how to shell and eat them. Start by putting a seed vertically between your molars (chewing teeth) so the seed holds in the indentations. Crack the seed gently, then use your tongue to separate the smooth seed from the rough shell. Finally you spit out the shell. This is harder to do than it is to describe and it takes quite a bit of practice to get it down smoothly. Eventually you can have a store of seeds in one cheek, crack them on the other side of your mouth and spit out the shells in a continuous stream.  

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