Common Questions

Mark Boyles, Canola Project Specialist, Oklahoma State University

What is canola and what are the uses of canola?
Canola is a low erucic acid oilseed crop developed from oilseed rape. Europeans have grown oilseed rape for 2000 years. It is in the Cruciferae (mustard) family and closely related to turnips and cabbage. Its main use is for edible oil and meal for feed.

What are the benefits of having a wheat / canola rotation?
Provide the Oklahoma wheat grower with a winter broadleaf rotational crop. Allow clean up of difficult to control broadleaf and grass weeds in current wheat production areas. Produce a profitable alternative crop. Potentially improve yield and quality of winter wheat planted after a canola rotation. Several current canola growing areas have shown improved wheat yields when planting wheat after canola.

What is the difference between winter and spring canola?
Spring canola is planted in March and harvested in Sept-October in the northern states and Canada. If planted in Oklahoma in the spring the heat in July and Aug burns it up. Winter canola planted in the fall (Sept) over winters and is harvested in June. Typically, winter canola will yield 20 to 30% more than spring canola.

When should winter canola be planted?
Optimum planting dates in the north western part of Oklahoma is between Sept 1 and Oct 1. or approximately. six weeks before the first killing frost. There is a chart currently available that lists the optimum planting dates for all the counties in Oklahoma.

Can winter canola still freeze out?
It has very good cold tolerance, but it can still freeze out. It is not necessarily the cold but dry soils combined with rapid fluctuation in temperatures. Like 70 degrees during the day and 10 degrees that night. This was not been an issue during the 2002/2003 or 2003 / 2004 seasons.

Does it make a difference whether you use liquid or dry fertilizer?
It does not make a lot of difference if you use liquid or dry fertilizer. Applications of 80 lbs of liquid nitrogen have been applied without noticeable burn. You will not see the burn like you do on wheat with liquid nitrogen applications.

Are P and K fertilizer necessary in canola production and how does canola perform in low and high pH soils?
Both are required for canola production. Requirements are very similar to wheat. As far as soil pH, canola grows best in a range of 5.5 to 8.3. Outside this range yields may drop off quickly.

How much nitrogen does it take to raise a normal canola crop?
The rule of thumb is 1/3 more that wheat, with one third applied in the fall and 2/3 of the N applied in the spring prior to bolting.

Is it necessary to use a starter fertilizer and if so, should it be with the seed, beside the seed or broadcast on top, and how much?
It should not be applied with the seed. If applied beside the seed there should be at least 1 inch separation. You may need to incorporate a starter fertilizer with P, K, and 25 to 30 lbs of Sulfur per acre. Always get a soil test and recommendations for canola

Can canola be top dressed in the winter like wheat?
Yes it can be top dressed in the fall and spring with nitrogen like wheat with dry or liquid fertilizer.

At any time can grass and broadleaf weed control chemicals damage the canola crop?
Use of any agriculture chemical can cause injury. But no significant injury from any labeled application of herbicide, insecticide, or fungicide has been noted. Most labels allow application from 2 to 4 leaves in the fall to prior to bolting in the spring. Applications of some pesticides after bolting in the spring can reduce yield.

Can you hurt canola by driving over it while frozen?
Yes, individual plants that are run over will be hurt, but overall yields of the field will not suffer.

What is considered an average crop of canola compared to a 40 bushel wheat crop?
Under the same growing conditions canola should make 85% of wheat on the same site. If it is a good year for wheat it will be a good year for canola. Canola weighs 50 lb/Bu compared to 60 lbs for wheat.

What type of equipment does it take to plant canola?
Canola can be planted with any typical equipment used to plant wheat. This includes alfalfa seeders.

How deep should canola be planted and how does canola react to no-till ?
The key is maintaining approx. ½ to 1 inch planting depth with good seed to soil contact in moist soil. Canola works well under no-till conditions. With no-till planters attention needs to be paid to making sure the planting slit is covered and firmly packed.

What diseases are common in canola?
The two major diseases are Blackleg and Sclerotinia Stem Rot. These presently will not be a problem in Oklahoma until we have a few years of growing canola. Because there are no common diseases between wheat and canola, a rotation back to wheat will solve many potential issues that might arise. Also the conventional winter varieties have genetic resistance to Blackleg.

On an average year, how many times would you have to spray canola for diseases, insects or weeds?
In general we see one application for weed control, none for diseases, and none to two for insects.

How many pounds of canola do you plant per acre? How many plants per square foot are required to produce a good crop?
It is recommended to plant 5 lbs per acre. Plant populations as low as 1 plant per square foot can produce a good crop.

What happens if you have a thin stand? Is it forgiving and will it branch out like wheat stools?
Yes, it a tremendous compensator for thin stands. The thinner the stand the more branching it does. Excessive branching may cause uneven maturity.

Would the seeding rate be different if you were planning on grazing canola?
Some information says plant it earlier and lower seeding rate by approx. 1 lb. Other information says plant at the optimum date for your area and raise the seeding rate by 1 to 2 lbs. Much information needs to be developed on grazing canola.

What are the recommendations for grazing canola?
Presently there are no guidelines for grazing canola. Although we know that after a first frost cattle will aggressively consume it. Overgrazing can seriously hurt seed yield. If the crop is grazed it needs to be done over a short period of time in the fall removing only half the forage.

In the spring can a late frost affect the canola crop?
Canola blooms for approx. three weeks and produces 50% more blooms than will ever set pods. If a frost hits during flowering it will knock out the flowers that were open that day, but will not hurt the flowers from the day before or the ones that open the next day.

Can canola be harvested standing or should it be put in a windrow?
It can be harvested both ways. The way that is best is dependent on your overall operation. Europe is all direct combining. In northern US and Canada most is put in wind rows at about 20 to 30% moisture and picked up when it has dried down.

How difficult is it harvesting the standing canola?
It is a little slower than harvesting wheat. It needs to be cut when it is ready.

Can canola be defoliated?
Yes there are defoliation products, but we do not expect defoliation products to be needed. In Oklahoma in the early summer 90 plus temperatures and 15 to 25 mile per hour winds do a fine job of drying down the crop.

How hard is it to market canola?
Presently Johnston’s Seed of Enid is buying this year’s crop. Several more sites will be available next summer.

What are greens and burns in canola seed?
Greens are immature seed that causes undesirable discoloration of the oil. This will not be a problem cutting canola standing. It maybe more of an issue if canola is swathed. Burns are canola seed that has overheated and has a burned odor to them. This will not be a problem unless it is stored improperly.

What percentage of the canola seed is oil?
For the currently available varieties we have available the oil content is in the high 30% range.

What moisture do you harvest canola at?
Best to harvest canola at 8 to 10% moisture. Stores best at about 9%. If the canola is > 12% you will have to air dry down before taking it to the elevator. Canola can lose 1 to 5% moisture in a day or two.

What percentage of shattering should we expect by harvesting canola standing?
If the crop is standing with good weather you should be able to harvest with less than 5% loss. You must get out and harvest standing canola when it is ready. Physical damage (high wind, hail, heavy rain, etc) will cause canola to shatter up to 50% after it is ready to harvest.

How does canola perform in low lying areas with poor drainage?
It performs poorly in soils with poor drainage.

Should canola be planted in rich bottom ground or can it also be planted in average to below average upland soils?
It will do well on most sites as long as the soil profile is well drained and other production factors are not limiting.

Can canola be stored on the farm for seed for the following year and should we worry about germination storing it on the farm?
It can be stored on the farm if it is a public variety. But it is harder to store than wheat. To keep the germination up it must not be allow to heat. With current conventional varieties and planting only 5 lbs per acre it makes good sense to purchase certified seed each year. Presently the conventional Wichita variety is approx. $1.00 per pound.

How easy is it to control volunteer canola the following year in wheat?
Current data from 2004 shows that it is very easy to control volunteer canola in wheat with all currently used broadleaf compounds. Most canola seed will sprout in the summer and not be a problem in the fall anyway.

Does canola have a deep tap root and is it capable of penetrating a hard pan?
Canola does have a deep tap root and can penetrate depths of 40”. Available information shows that it can help reduce hard pan situations.

What benefits are there to Roundup Ready canola?
Good weed control of all commonly found wheat difficult to control grasses and broadleaves in wheat. Good canola tolerance has also been noted with all current varieties under development. No soil residual for rotation to other crops.