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Available in 1,000 seed, 5,000 seed or 10,000 seed foil packs. Sunflowers work well
as a full season crop in rotation with corn, soybeans and/or sorghum. As a
double crop after wheat, sunflowers are an equally good choice with soybeans.
Regardless of whether they are grown as a single crop or double crop, sunflowers
should not be planted in the same field more than once every three to four
years. Sunflowers, like soybeans, do not leave very much residue; so on
erosive fields consider seeding a fall cover crop after sunflowers.
Sunflowers generally grow best on well drained soils, are tolerant of clay loam
or silty clay loam soils and perform comparatively well on sandy loam soils.
They should not be grown on wet soils, but may be a good choice for bottom
ground that doesn’t dry out until early summer, since the sunflowers can be
planted relatively late. Variety Selection Planting
Sunflowers should be planted 1 to 1 1/2 inches deep. Row spacing studies
have shown that sunflowers do not yield better in narrow rows, whereas wide rows
are preferable to allow cultivating for weeds or use a row crop header.
Sunflowers are not particularly sensitive to seeding rate, since head size (and
seed number) per plant will increase in a thinner stand. Seeding rates can
be from 15,000 to 25,000 plants per acre. Sunflower seeds vary in size, so
seeding rate based on weight must take into account seed size, but will be roughly
3 to 4 pounds per acre. Number 2 sunflower seeds are largest, while number
5 are smallest. Most sunflower seed available is sized as a 3 or 4.
Size of the seed can affect what type of planter modifications are necessary,
such as buying new seed plates or finger pickups. Planting
sunflower can begin anytime after soils have warmed to 50 degrees F. ( Fertility
Sunflower has modest fertility needs, but does respond to nitrogen. When
following soybeans in the rotation, roughly 50 to 70 lbs. N/acre is appropriate.
Following a non-legume, about 80 to 100 lbs. N/acre is suitable. Animal
manure or a legume cover crop can reduce or eliminate need for N fertilizer.
One option is to spring plant a legume cover, such as Austrian winter peas in
early April, let the legume grow for 2 months, then incorporate the legume and
plant the sunflower in early June. This approach can eliminate the need for N
fertilizer if good legume growth occurs. For sunflower planted double crop
after wheat, apply about 60 lbs. N/acre if the wheat stubble is tillage
incorporated, or about 80 lbs. N/acre if the sunflower is grown no-till in the
residue. P and K should be applied based on soil test recommendation; for
double cropping, extra P and K for the sunflower can be applied to the wheat the
previous fall. On sandy soils, sunflower is often responsive to extra
potassium fertilizer. Sunflower appears tolerant of soils with a pH down
to 5.5, but consider liming if the pH is below 6.0, to improve nutrient
availability in the soil. Starter fertilizer for sunflower will usually be
beneficial only in cool soils of early spring, and should not be placed in
direct contact with the seed. Weed
Control One of the real advantages of sunflower is that its vigorous
growth and robust size make it very competitive with most weeds. However,
weeds must not be allowed to get a head start on sunflower. Weeds can be
controlled either through herbicides or tillage, but most sunflower producers in
Insects
Sunflower is similar to corn in that a lot of insects like to eat it. Some are
occasionally a problem, and a few are worth scouting for, possibly needing
treatment once in awhile. At the seedling stage, there is rarely a problem
unless a heavy infestation of cutworms are present. As the plant grows,
many insects feed on sunflower foliage, including grasshoppers and caterpillars,
but seldom do they cause economic damage. The real stage to be scouting
for insect pests is once the flower bud has begun to develop. Head clipper
insects which attack the stem right below the head can cause the whole head to
fall off, but are not too common. The main threat to sunflower is
sunflower moth or banded sunflower moth. Ideally, the adult moths should
be identified through scouting, and if present in sufficient numbers, should be
sprayed before larvae become established. Once the eggs have hatched and
larvae have moved inside the head and seeds, insecticide control is very
difficult. Later planting ( Diseases
In cool wet soils, seeds or seedlings may be attached by fungi, so seeds are
typically treated with fungicide. Various leaf and foliar diseases will
cause surface spots or yellow patches, but do not impact yield. Probably
the greatest disease threat to sunflower is sclerotinia (white mold), which is
also found in soybeans, canola, and certain other broadleaf plants. Using
good rotation practices, including not planting sunflower in a field more than
every three to four years, can reduce likelihood of disease. *Pesticide products are mentioned in this guide
only as a starting reference point for product use, and are not a guarantee that
a label for the product is applicable to your particular locationi. For
latest information on use of a pesticide, consult the product label or a company
representative. Harvest Sunflower
seeds are generally physiologically mature when the back of the flower head is
yellow. When the head turns brown on the back, seeds are usually ready for
harvest. In some cases, harvesting at high moisture may be useful to avoid
bird damage or reduce loss from lodging or seed shatter. Platform (wheat),
row-crop, and corn heads have all been used successfully with sunflower.
Row-crop heads are perhaps the best choice because they can be used without
modification. Corn heads need to be modified with a stationary cutting
knife before use with sunflower. Platform heads can be used without
modification, but often have a higher amount of seed and head loss than a row
head. Adding pans to the front of the platform, and/or modifying the reel
can improve efficiency. Combine settings must be adjusted for sunflower
versus other crops. Airspeed should be lower, due to the lighter weight of
sunflowers. The concave should generally be run wide open (on a rotary
combine, a rotor-to-concave setting of 3/4 to 1 inch is appropriate). A
bottom screen of 3/8 inch, and a top screen of 1/2 to 5/8 inch is typical.
Cylinder speed should usually be in the range of 250 to 400 rpm. The
overall goal of the threshing process should be passing the head through nearly
intact through the combine, or in a few large pieces, with all developed seed
removed from the head. If the head is being ground up into small pieces,
there will be excessive trash in the grain. Storage
During colder periods, sunflower can be safely stored at 10% moisture or
less, but during warmer months the storage moisture should be at 8% or less.
When taking a moisture reading on sunflower seeds that are being dried in a bin,
keep in mind that the hull dries faster than the kernel. Thus, a moisture
reading taken on sunflower being dried may be artificially low; to get a more
accurate reading, place some seed in an airtight jar overnight and take moisture
reading the next day, after the hull and kernel moisture have equalized. Bins with perforated floors work better for
drying sunflower than those with ducts. If aeration is not available,
sunflower should be rotated between bins to avoid hot spots developing in the
stored grain. When excessive trash is present in the harvested grain,
cleaning before storage can greatly reduce incidence of storage problems.
Ambient air can be used to cool and dry sunflower. If heated air is used,
generally a 10 degree F. increase in temperature over ambient is sufficient to
increase rate of drying. Be aware that sunflower dries more rapidly than
corn or soybeans, and should be monitored to avoid over drying. Sunflower drying has a higher risk of fire
hazard than some crops. The primary problem is that small fibers rub off
the sunflower hulls and float in the air, and these fibers readily burn. A
few tiny fibers burning will not necessarily start a fire, but if combined with
over dried grain, may lead to a bin fire. Avoiding use of propane heat with
an open flame will eliminate this risk, but if heat must be used certain
precautions can be taken. The air intake for the dryer blower can be
turned into the wind, allowing clean air to pass over the burner rather than air
with sunflower fibers. Monitoring the bin during hot air drying, and
avoiding over drying, can greatly reduce the risk of a bin fire. Other key steps in storage include cleaning the
bin and grain handling equipment before storage, and monitoring the bin for
insects. Avoid creating a peak or cone of grain at the top of the bin,
since moisture, and possibly insects, will tend to congregate in that spot.
Sunflower grown for the snack food (confectionery) market must be handled with
extra care, cleaned well, and be free of insect damage to meet food grade
standards. Test weight (pounds of seed per bushel) of
sunflower will vary because of different seed sizes, but typical test weights
for oilseed sunflowers are 28-32 lbs./bu. (U.S. grade standard is only 25 lbs./bu.).
Due to the low test weight, high sided semi-trailers are often used when
sunflower is hauled long distance in order to carry more grain and reduce
transportation cost. Increase Your Sunflower Yields Planting Tips for a Successful Field The 2002 USA Sunflower Survey showed that growers in the High Plains lost hundreds of pounds of yield due to poor stand establishment. Poor stand establishment was a close second to drought as the number one yield robber. Sunflowers will compensate if you have both even emergence and plant spacing in your field in spite of having several thousand less plants. Fields that have plants emerging for several weeks with skips and doubles can decrease yields by 400 to 500 lbs. PLANTER ADJUSTMENTS Your planter is like a machine gun. It has to shoot out 13.5 seeds/second, if you have an eight row planter seeding 20,000 seeds at 5 mph. Sunflower seeds have more variation than most other seeds. That is why it is so important to clean and adjust your planter before planting your sunflowers. Also use the recommended plates, fingers and air pressure to help avoid skips, doubles. Run your planter at recommended speeds. WOODY HULL Sunflowers have evolved in the High Plains over thousands of years. One survival mechanism is its woody hull which prevents germination during dry conditions. To insure even germination, seed must be placed in soils with adequate soil moisture and good seed to soil contact. SEED DEPTH Sunflower seed needs to be planted at depth of 1.5 to 2.5 inches. FURROW CLOSING Sunflower needs to have excellent seed to soil contact. Again because sunflowers have a woody hull, closure of the furrow becomes more important than for corn and most other crops. SOIL TEMPERATURE Soil temperature needs to be at 50° or more at seed depth (1.5 to 2.5 inches). Planting sunflower seed into cold soils may cause seed to go into dormancy and can delay germination. INSECTS Insects like wire worms and cutworms can drastically reduce stands. Use approved chemicals to control insects. WEED CONTROL Satisfactory weed control is essential. Use labeled products and apply them as recommended. Know the field's weed history and control accordingly. HARDPAN Sunflowers have a deep rooting taproot but will not penetrate a hardpan. Break up any hardpan prior to planting. |
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