Edit 2/24/2024: At the end of the day, the big fact, that nobody bothers to say, that I didn’t realize, is that you have to harvest your mustard in the cool of autumn. I guess I should have taken a hint from the fact that North American Mustard Belt is in Canada. Restated, you can’t harvest mustard, in the summer, in Virginia. By that I mean you can’t get flavorful, evenly-cured, pleasantly-edible, good-looking mustard seed from mustard planted as a spring cover crop, in Virginia. Which is a pity, as mustard makes a dandy cover crop here.
Whether or not I can plant mustard mid-summer, and get a decent crop of pleasantly-edible seed in the fall, in Zone 7 Virginia, I will find out this year.
Original post follows.
This is another one of those notes-to-myself posts. I’m just getting a bunch of facts that I need in one place, so I can’t lose track of them. In this case, the facts are about growing and harvesting yellow mustard in the home garden.
I only make two points in this posting.
First, I ought to expect to get about quart of mustard seeds from every 100 square feet of planted area.
Second, I should harvest yellow mustard well before the “dry and crispy” stage shown in most internet videos on this topic. Professional farmers either harvest it when the field is a mix of green-and-gold, seeds are all fully-formed but up to 25% remain green (for “swathing”, or cutting it to let it dry in the field). Or they can wait until all seeds are yellow and the moisture content is no lower than 12%.
Edit 3/8/2024: A good part of the reason you can’t harvest mustard, in Virginia, in the summer, is that the green mustard seed will NOT finish ripening in the Virginia summer heat. The heat destroys the enzymes in the plants required to finish maturing the remaining green seeds to gold. As a result, what is described as a standard technique for actual (Northern, fall harvest) mustard farmers (swathing) does not work at all in the middle of a Virginia summer.
Search this website for other posts on growing, threshing, winnowing and using home-grown mustard seed.
FWIW, this advice applies only to yellow mustard, not to other varieties.
Background: The information gap for home vegetable gardening.
It’s tough to get reliable advice for your home vegetable garden.
On the one hand, most internet-based advice for home gardeners is astoundingly unreliable. You name a topic, and there’s somebody out there making a lot of happy talk, or mistaking luck for cause-and-effect. Or just plain puffing up their successes with good dollop of horse manure.
At the minimum, nobody brags about their failures. And that imparts an overly-optimistic spin to the advice and discussion aimed at the home market.
On the other hand, advice for professional farmers is almost always fact-based and accurate. The problem is that it’s almost entirely oriented toward industrial farming methods. By that I mean, heavy use of chemicals of all sorts. And completely ignoring methods that might be used in a home garden, but would be impractical or unprofitable for commercial farms.
So, in this post, I’m reading through some literature on mustard growing, aimed at commercial farmers. Tossing out all the chemical-oriented advice. Just trying to get a handle on how one is supposed to grow and harvest yellow mustard.
That’s because, last year, I flunked Mustard Growing 101. Actually, the growing was easy. Growing mustard is a pleasure. Yellow mustard is a no-care, pretty, bee-friendly, effective deer-proof ground cover. It was the harvest-to-table portion where I did nothing right. That, based on the advice I read on the internet, aimed at the home gardener.
Right now, I have about 600 square feet of yellow mustard in my back yard. It’s mostly finished flowering, and it’s getting to the point where I should harvest it.
So this post is me, getting my facts straight, for the harvest-to-table portion of mustard growing. Based in part on everything that went wrong last year.
Expected seed yield: About a quart per 100 square feet.
Before I go to the trouble of harvesting the stuff, I’d like some assurance that it’s worth the effort. If the best I can expect is a few tablespoons of seed, I’m not going to bother.
So, if everything goes right, how much mustard seed should I expect to collect, from my 600 square feet?
Answer: If I’m average, from my 600 square feet, I should expect more than a gallon and a half of yellow mustard seed. That ought to be enough to make about 3 gallons of mustard (the condiment). So, as long as the harvesting and winnowing isn’t too onerous, I judge that to be well worthwhile.
Mustard responds well to fertilization, particular heavy fertilization with nitrogen. By contrast, I did nothing but spread it on some beds at the back of my yard. So I’m not sure how well the commercial yield data will apply to my garden and climate.
The only real takeaway is that the plausible yield is quarts of mustard seed, not tablespoons of mustard seed.
When to harvest: Earlier than you might think.
Typical advice to the home gardener is to harvest fully-dried seeds
If you look at (e.g.) YouTube advice for the home gardener, you’ll see a lot of completely crispy mustard plants. No hint of green, with the stalks truly dead and completely dry.
At that point, if you harvest the seeds, they are fully dry and ready to be put into storage. But, see below, that’s NOT what farmers do.
I took that advice last year, and I regretted it for a variety of reasons. The powder-dry stalks break up and put a lot of hard-to-separate organic trash in with your seeds. The seed pods themselves get somewhat fragile (see “shatter”, below), so you lose seed that way.
But mostly, if you let the seed sit around long enough, some of it turns black. Whether this is normal for mustard, or whether it’s fungal growth, I can’t tell. All I know is that, in the end, it was all-but-impossible to separate the discolored seed from the yellow seed. Hence the mottled appearance of last year’s final product, below. This is what was left after I’d spent time removing most of the dead-black seeds.
What do actual mustard farmers do?
Actual mustard farmers harvest seeds before they are fully dried.
Here, I’m going to synthesize from several sources aimed at commercial mustard growers. But the bottom line is that you can harvest yellow mustard early, when the seeds are fully-formed, but the field (and the seeds) are a mix of green and gold. Or you can wait until the mustard is just barely fully dry, with (seed?) moisture content of around 12%.
Either way, as I read it, under either method, farmers harvest mustard before the seeds are dry enough to be stored. Which is at an earlier stage than the advice to home gardeners would suggest. If you harvest like a commercial farmer, the seeds then need to be dried down to below 9% moisture content for storage.
You can cut yellow mustard as long as the seeds are fully formed, the bed of mustard has a yellow-and-green appearance, and three-quarters of the seeds are yellow. The remaining green seeds will turn yellow as mustard finishes drying.
Or, you can wait until the yellow mustard seeds are dried to about 12% moisture. The seed should be uniformly yellow at that point, but this is well before the seeds are dry enough to be stored.
The point being, mustard farmers harvest well before the level of “crispiness” shown in most internet videos on this topic that are aimed at the home gardener.
Sources:
- Crop Profile for Mustard in Montana, Prepared Jan., 2002
- EM 8796 • July 2002 Edible Mustard D. Wysocki and M.K. Corp
- Government of Manitoba, crops management, mustard
- Agriculture marketing.com, oil seeds and mustard
- University of Wisconsin, mustard.
Key terms defined
Swath or direct combine, defined. Roughly speaking, your options are to “swath” the mustard, or “direct combine” it. I’m pretty sure that “swathing” means cutting it and leaving it in the field to dry. The swaths are then gathered, once dry, and threshed to release the mustard seed. The actual cutting for swathing should be done in relatively moist conditions, e.g., early morning. Direct combining means cutting and harvesting the dry mustard plants in one step, without leaving them in the field to dry first.
To sum up: You can cut it when it’s still partly green, and let it dry (swathe it). Or you can let it mostly dry, and cut the dried stems (direct combining).
Shattering, defined. If the pods split open and spill the seed inside, that’s “shattering”. The dryer the pod, the rougher the handling, the more likely it is to shatter. Yellow mustard is more resistant to shattering than other mustards. The advice below applies specifically to yellow mustard, not to other varieties.
Reel, defined. This is a the part of a combine that, in part, lifts crops up off the ground, so that they stand up and can be cut. The fact that most of the advice below mentions the use of a reel matches what I see in my garden, in that the mustard droops over when it is finished growing and is in the process of filling out its seeds. The plant is green, and in most cases the leaves remain, but it no longer stands upright on its own.
Excerpts from sources, emphasis mine.
Montana:
Wind, rain and normal drying generally does not cause mustard to shatter before cutting. But, the actual harvesting operations can cause severe shattering losses when the crop is overripe or extremely dry. Yellow mustard can be straight combined if the field is not weedy and the crop is uniformly ripe. When direct combining, wait until the crop is mature and dry. The reel may cause shattering when straight combining but it can be removed or lifted above the crop if the stand is good. If the reel is needed, it should be reduced in speed and half the bats removed. Many growers of yellow mustard prefer to straight combine while the crop is still tough (12-15 percent moisture) and then artificially dry. This results in seed of uniform quality. Brown and oriental mustard varieties are generally more susceptible to shattering than the yellow types and should be swathed. Yellow mustard should be swathed if the crop is weedy or uneven in maturity. Mustard should be swathed following general leaf drop when overall field color changes from green to yellow/brown and early enough to avoid shattering. Pods selected from the middle of the racemes of several plants in areas representing the average maturity of the field should be examined for physiological maturity of the seeds. Most varieties are at the optimum maturity for swathing when upper pods have turned and seeds are brown or yellow. The remaining 25 percent green seeds will mature in the swath prior to harvest.
Edible mustard
Wind, rain, and normal drying generally do not cause mustard to shatter before cutting. Yellow mustard can be direct-combined if the field is not weedy and the crop is uniformly ripe. The harvest operation can cause some shatter if the crop is overripe or extremely dry. When direct-combining, wait until the crop is mature and dry. You can remove the reel or lift it above the crop if the stand is good. If the reel is needed, operate it at a reduced speed.
Manitoba:
Yellow mustard is resistant to shattering and therefore can be straight-combined. If the crop is to be swathed, seed moisture should be around 25%.... Mustard is considered ready to combine when moisture reaches 12-13% or less and no green seed can be found.
Agricultural marketing.com
Shattering can be a concern so if direct combining, do so before the pods are too dry and seeds have 12-15% moisture. Swathing soon after the crop has reached physiological maturity can help reduce shattering.
U Wisconsin:
The normal maturation of the crop, wind, and rain do not cause shattering before cutting. However, the actual harvesting operations can cause great shattering losses when the plants are overripe. Yellow mustard does not shatter readily and can be straight combined if the crop has matured uniformly (10% moisture) and is free of green weeds. If the crop is weedy or uneven in maturity it should be swathed. Swathing, if deemed necessary or preferred, should be done when 60 to 70% of the seed has turned yellow-green. Plants should be cut just beneath the height of the lowest seed pods. The swath will then settle into the stubble and reduce the chance of being blown by high winds. Yellow mustard does not cure quickly. Straight combining is therefore recommended at 12 to 13% moisture, followed by artificial drying, to obtain uniform quality and highest yield.