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Learn about Sunn Hemp and other Petcher seeds.
What is Sunn Hemp?
Sunn Hemp, a tropical legume, is used in many tropical countries as the number one soil builder and cover crop for reclaiming poor land.There are millions of acres of this crop grown in other countries. Brazil calls it their number one soil builder. Sunn hemp is originally from India and has been grown since the dawn of agriculture. It has been grown as a green manure, livestock feed for forage, hay, and for non-wood fiber.


In 1931 USDA proclaimed sunn hemp excellent for building the soil. Since that time the use of sunn hemp in the US was almost unheard of. It has only been in the past few years that knowledge and benefits of this plant have taken root in the U.S.

Sunn hemp is a tropical legume whose claim to fame is that, 60 days from planting, it is typically over six feet tall, adds 120 pounds of Nitrogen to the soil, 10 pounds of residual Phosphorus and 80 pounds of residual Potash transfers from the subsoil to the topsoil, supplies four tons of organic matter, is a great soil builder, as well as increasing drought tolerance and yield and cash value of the next crop.

All livestock and wildlife thrive on sunn hemp. The leaves of sunn hemp are 30 percent protein. We have not found yet anything that eats vegetation that does not thrive on sunn hemp.  

Sunn hemp is not an invasive weed. In fact, it smothers out 99.9 % of all weeds and is allelopathic to Palmer Amaranth. The sunn hemp will not flower and go to seed until the days start getting shorter (mid September in Alabama). There is not enough time for those seeds to mature in our area after flowering.  

Sunn hemp is resistant to root-knot and Reiniform nematodes. Root-knot and reiniform nematodes are a major pest in South Alabama agriculture, and root-knot nematodes are a pest in almost every home garden in South Alabama. Gardeners could plant their spring crop and then in June, July, or August plant the sunn hemp.

Sunn Hemp Production Guide:

Planting Time: Sunn Hemp is a tropical legume. The seed will germinate at soil temp of 48°F However, the plant grows much better as the soil temperatures and night temperatures are much warmer. Anytime after the last frost will work but waiting for warmer temperatures makes the plant grow much better.  

Seeding Rate: Our recommended seeding rate is 15 lbs. for a cover crop and 25 - 30 lbs. per acre for grazing. We start at the low range to save costs for growers. Many growers are upping their seeding rates after seeing the benefits.

Seed Depth: Seed will come up on top of the ground to 2 inches of depth.  Planting 1/4 - 1 inch deep is best.  

Soil Test:  Sunn hemp will grow on a pH from 5.0 - 8.5 so your soil will not need liming for the it to grow. It needs no fertilizer. However, it will grow better if ample Phosphorus and Potash are already in or added to the soil.

Inoculant: In the Southern States, we are not recommending the use of inoculant as there is typically plenty inoculant in our soils. In Northern states sunn hemp is responding to the use of peanut inoculant.   

Drought Tolerance: Sunn Hemp grows best on sandy, well drained soil. It does not like hard, packed clay. It does take moisture for it to germinate, and then another good inch of rain to get it going. After that, it is fairly drought tolerant.  

Plant growth: For the first 30 days, the plant is sending down roots and top growth is very slow. After that, the plant usually grows rapidly and typically reaches six feet in growth by day 60.  

Start of Grazing:  We have found the best time to be when the plant is 32 - 36 inches tall. At that time, the livestock will eat the terminal of the plant down to about 18 inches. The stem will bud back ou shortly, making new branches and leaves. This will provide more vegetation for grazing. If grazed too short it will take longer for the plant to regrow. If allowed to get too tall, livestock will typically knock the plant down instead of allowing it to regrow.  

Sunn hemp for hay and silage: Yes, this can be done. Best to use a mower conditioner. Cutting the sunn hemp when 4 - 5 feet gives the best quality of hay. Cutting the sunn hemp about 4 inches off of the ground may allow it to regrow if there is plenty of moisture. Making hay or silage from sunn hemp has not been easy, and may be disappointing for you.  

Disease: Sunn hemp is fairly resistant to disease. Fusarium wilt is the most common to affect it. Rotation is a must. After growing sunn hemp for two seasons, it is best to rotate to another crop.  

Insects: Although sunn hemp does attract grasshoppers and other insects, they are rarely a problem. Even if the grasshoppers or army worms completely defoliate the plant, the leaves will grow back. Seldom has anyone benefited by by spraying for insects on sunn hemp.  

Weed Control: This crop may prove very beneficial in ridding land of unwanted weeds. Sunn hemp does have allelopathic activity on some weeds, including palmer amaranth and its very rapid growth almost totally chokes out other weeds. It appears to smother out most if not all other weeds including pig weed, palmer amaranth, and nutsedge.

Nematode Control: Sunn hemp is resistant to root-knot and Reiniform nematodes. Root-knot and Reiniform nematodes are a major pest in South Alabama agriculture. And root-knot nematodes are a pest in almost every home garden in South Alabama. Sunn hemp would be a tremendous benefit in reducing nematode populations in almost every home garden in our area. Gardeners could plant their spring crop and then in June, July, or August plant the sunn hemp.

Termination: For a cover crop, it is best to let sunn hemp grow from 60 - 90 days before terminating. At six feet tall there is usually a perfect Carbon/Nitrogen ratio in the plant.  If allowed to grow longer the plant will produce more Nitrogen, but will also produce more Carbon. The Carbon fiber in the plant may tie up the Nitrogen in your soil for a few months.  

Not an invasive weed:  The sunn hemp will not flower and go to seed until the days start getting shorter (mid-September here). After flowering there is not enough time for those seeds to mature in our area.  

Sunn hemp is perfect for the home gardener, organic farmer, row crop, turf, wildlife and livestock farmer.  We encourage you to give it a try on your farm.

Is It Safe for Grazing?

This article was written by Dr. Jorge A. Mosjidis, Plant Breeder at Auburn University.  Many of his plant releases have been extremely valuable to us. Several have been AU Grazer Ceresia Lespedizia and AU Golden Sunn Hemp. He is a good friend and we would like to thank him for his hard work and diligence. His research proved sunn hemp to be safe for grazing. Please see and review his findings.  

The Facts about Sunn Hemp Toxicity          

Jorge A. Mosjidis *a, Joan M. Burkeb and Joseph B. Hessc


Sunn hemp (Crotalaria juncea L.) is an annual plant widely grown in the tropics. The genus Crotalaria includes some species known to be toxic to animals. Development of seed-producing cultivars for the continental United States at Auburn University, AL, has raised the question of whether its seeds and forage are toxic. This review will present the evidence reported in the literature on the presence of toxic compounds in sunn hemp seed and foliage and other Crotalaria species found in the United States and their effect on animals. Results from research on sunn hemp demonstrate it is a valuable source of forage without toxic effects. The seed does not cause acute toxicity to domestic animals because it has only a small amount of the toxic pyrrolizidine alkaloids characteristic of the genus Crotalaria. Therefore, its presence as a feed contaminant does not pose a problem. However, sunn hemp seed should not be incorporated in animal diets because, depending on the amount in the diet and the length of time that the diet is fed, it may cause weight loss and potential death. Conflicting reports found in the literature regarding seed toxicity of C. juncea appear to be caused by the amount of seed included in the diet, length of time the diet was fed, and animal species that consumed it. Statements indicating that sunn hemp forage is toxic seem to be due to misinterpretation of the literature and unwarranted extension of the toxicity problems found in other Crotalaria species to sunn hemp.


This mix of Sunn Hemp and Quail Haven Soybeans is one of the Ultimate Mixes for summer grazing.  A two-acre field was planted mid April. In June, when Sunn Hemp was 32” tall grazing was started. Timing is critical. If the Sunn Hemp is too tender the livestock will eat it to the ground. If too tall (6’) the livestock will break the plants and they will die. With control grazing, 100 goats and two horses were allowed to graze this mix for the entire summer. We planted another two-acre field of the same mix for a late season protein reservoir. This field was kept untouched except for a few deer grazing. The Sunn Hemp mix grew to 10’ in height by mid-August.  Livestock will break the tall Sunn Hemp plants as they graze. Goats will be allowed to graze this field until Thanksgiving or 28°F kills the Sunn Hemp. A major key to success is to control graze. One hundred goats, if left on their own, will demolish this two-acre field in a few weeks. However, allowing them to graze for one hour a day will greatly improve the herd’s health

Sunn Hemp for Reclaiming Poor Land


Dick Higbee, former president of Alabama Pecan Grower’s Association, planted 10-acres of Sunn Hemp on extremely poor land that would not even grow a soybean. The following year, both corn and soybean were planted in this field, and both performed well. While prior to Sunn Hemp planting, the soil had become useless. Planting the Sunn Hemp changed the soil from the worst to the most productive.

Sunn Hemp’s claim to fame is that in 60 days from planting it typically is 6 feet tall and produces 120 pounds of Nitrogen (N), brings up from the subsoil 20 pounds of Phosphorus, 80 pounds of Potash, and produces four tons of organic matter. It greatly suppresses root-knot and reiniform nematodes and weeds.

The Sodbuster Radish is also an excellent soil builder.  The tuber averages 10 - 20 inches long and 2 - 3 inches in diameter. The taproot can penetrate as deep as six feet, alleviating compaction. It is excellent for scavenging residual plant nutrients, especially Nitrogen. It typically releases 80 lbs of Nitrogen to the next crop and suppresses nematodes and weeds. It provides five tons of organic matter to the soil.  

Sunn Hemp and Weed Control


Sunn Hemp smothers out 99.9 percent of all weeds and is allelopathic to Palmer Amaranth. Any time you do not have a crop on your soil, fill those gaps with Sunn Hemp or Sodbuster Radish. Sunn Hemp in the summer followed by Sodbuster in the winter will totally rebuild your soil and dynamically improve your next crop as well as greatly suppressing weeds. Sunn Hemp may be planted up until Sept 1 in Southern areas.

After corn harvest, in late August through mid-October, plant the Sodbuster Radish. The Sodbuster is also excellent at suppressing weeds and is an excellent soil builder. The plants emerge quickly and within 30 days have a total leaf canopy that greatly suppresses weed competition. The tuber averages 10 - 20 inches long and 2 - 3 inches in diameter. The taproot can penetrate as deep as six feet, alleviating compaction. It is excellent for scavenging residual plant nutrients, especially Nitrogen. It typically releases 80 lbs of Nitrogen to the next crop. It also suppresses nematodes and typically suppresses 99.9 percent of all weeds. It provides five tons of organic matter to the soil.  

Sunn Hemp For Cattle

Sunn Hemp for cattle grazing is quickly spreading across the U.S. To my knowledge, no one had tried this in the U.S. before Petcher (it had proved to work very well for sheep and goats and for wildlife). I allowed my one cow “Mertle” to graze sunn hemp for three years, with zero negative affects. Several friends in the cattle industry decided to try it also. Then, after four years of very successfully grazing cattle on sunn hemp, we decided to move forward.

As a Forage Sunn Hemp leaves are 4 - 5 percent Nitrogen, equal to 25 - 30 percent Protein, 22 - 28 percent NDF, 22 - 27 percent ADF.  Stems are 1.3 - 1.7 percent Nitrogen, equal to 8-10 percent Protein, 74 - 76 percent NDF and 64 - 65 percent ADF. It is a very nutritious forage.

Start grazing when the plants are 32 - 36 inches tall.  Livestock will eat the terminal the top portion of the plant down to about 18 inches. Only the stem will remain. At this point take the cattle off. With moisture the plants will re-bud and put on new branches. This regrowth provides more leaves and forage than the original plant could produce.  This regrowth will take only a week or so. Many cattlemen are on a 10 - 30 day rotation.  

Often cows do not eat it the first day they are turned on to it. However, they quickly learn to enjoy it and by day 7 they are usually very addicted to it. One hour per day is sufficient for the cattle to receive their protein fix. Allow them to turn into other pastures such as Bahia or Bermuda grass.  

We are using zero fertilizer when planting our sunn hemp pastures. Typically, the winter forage crops planted behind sunn hemp will need little to no fertilizer as well.  

The daily gain of cattle on sunn hemp during the heat of summer has been around two pounds per day. If managed properly the sunn hemp will continue to grow until frost.  


The first on-farm research began on Elias Higdon's Farm in Grand Bay, AL. At that time, very few people in the U.S. had tried grazing cattle on Sunn Hemp.

This Sunn Hemp 10 lb. and Quail Haven Forage Soybean 10 lb./acre seeding rate is 30 days old and 24 inches tall.  His cattle have been grazing earlier planted Sunn Hemp fields for two weeks now. Cattle seem to be a little slicker and healthier. We are taking plant samples of the forage, watching the cattle and documenting as much information as possible. Higdon's knowledge of cattle and desire to pioneer this new crop is a tremendous benefit to all of us. Zero fertilizer was applied to his 275 acres of this mix. Cattle prefer this grazing over their Bermuda and Bahia grass pastures. Higdon’s cattle will enjoy 90 days or more of grazing this high protein feed during the summer months when protein is limited and expensive. In September, the forage will be terminated by mob grazing and then planted with cereal rye and “Lunch” Radish. The winter mix following sunn hemp should need no additional fertilizer. As a Forage Sunn Hemp leaves are 4 - 5 percent Nitrogen, equal to 25 - 30 percent Protein, 22 - 28 percent NDF, 22 - 27 percent ADF.  Stems are 1.3 - 1.7 percent Nitrogen, equal to 8-10 percent Protein, 74 - 76 percent NDF and 64 - 65 percent ADF.  We will keep you posted as this experiment proceeds.

Higdon’s neighbor Calvin Freeland, who farms 540 acres of soybeans, is very excited about the Sunn Hemp experiment, primarily because the deer have left his soybeans alone and are helping the cattle graze the Sunn Hemp.  

For Anyone Serious About Raising Cattle…


If you are serious about raising cattle, do yourself a favor and look into Sunn Hemp summer grazing. This summer legume requires no fertilizer and supports the growth of other crops grown with it.  

Several mixes are presently being used.  

  • Sunn Hemp (15 lbs. per acre) with Red Ripper Cowpeas (10 lbs.) and Apache BMR Pearl Millet (5 lbs.) is a good choice.
  • Sunn Hemp (15 lbs. per acre) Red Ripper Cowpeas (10 lbs.) Apache BMR Pearl Millet (5 lbs.) Buckwheat (5 lbs.) Sun Flowers (2 lbs.) is an excellent choice.     

These mixes are dramatically improving herd health over the summer when available forage protein is typically low. The sunn hemp is greatly improving soil health and also providing soil nutrients for the following fall and winter forage crop. Some growers are now on a year round zero fertilizer program. This is a tremendous savings to input costs on these farms. Growers are also reducing the need for hay and grain.

Bottom line, healthier cattle and more money in your billfold.


Sunn Hemp: A Cattle Favorite

Dear friends,

As fall is approaching we are pleased to inform you that we have the perfect forages for the season. Cliff and Kay began grazing their South Poll cattle on Sunn Hemp 34 days after planting. With a passion for their South Poll grass-feeding operation, they are pleased to see how well the Sunn Hemp is doing. They are excited about trying the cool season forages of "Cosaque" Black Oats, Thunder Ryegrass, Lunch Radish, Crimson Clover, and MiHi Persian Clover.

A special thank you to Cliff and Kay White for helping us pioneer these new crops.


Stagger Planting

Our Sunn Hemp grazing mixes, planted in April, May and June, have done very well. Many growers are planting this same mix in July and August. During this time, it usually takes only 35 days to grazing. These later plantings are much stronger going into the fall, allowing us to graze to almost Thanksgiving. The earlier Sunn Hemp plantings tend to fizzle out by early September so we mob graze or terminate those fields and get them quickly planted into our Cosaque Oat Fall mix. If we receive good moisture the Oat plantings are ready to graze by late October. Livestock can be rotated between the Sunn Hemp and the Oat pastures at the same time.  

Stagger planting is another way to ensure nutrient rich forage for your livestock.


Sunn Hemp has been used in other countries for goat production for many years. Our research at Petcher Seeds and on many goat ranches has continued to prove that goats and sheep thrive on sunn hemp. We would like to especially thank Bob and Marilyn Seleska with the Southeast Kiko Association and its many members for continuing to spread the use of sunn hemp for sheep and goats.  

Why goats thrive on sunn hemp  

First of all the leaves of the plant are over 30 percent Nitrogen. This boost in protein results in phenomenal herd health. At present there are no known toxins in sunn hemp that reduce parasites in goats. However, the fact that the goats will be mostly upward browsing has another dynamic effect on the herd as they will be ingesting few, if no worm eggs. The plant grows straight up, with leaves coming off the main stem. It is very important to let the sunn hemp achieve at least 32 inches, preferably 40 inches in height, before allowing the goats to graze. This typically will be around 45 days after planting. This allows time for the main stem to become a bit steamy and then the goats will eat just the leaves. If the stems are mowed below 12 inches, the sunn hemp may die instead of producing fast regrowth. If the sunn hemp is too tall, six feet or more, the goats may walk the plant down to eat the leaves and this usually kills the plants. So control grazing is a must if you only have a small patch of sunn hemp. Allowing the herd to graze for one hour per day is ample. If unable to control graze everyday, allowing the herd to graze at least once every four days will produce dynamic herd health.  

In 2010, “Sunn Hemp as a Summer Forage for Goats” research test was conducted in Southwest Alabama. An 80-head goat herd was control grazed on sunn hemp with no wormer or medication for the entire summer. At a second location ten miles away, a 100-head goat herd was managed on full feed, wormer and medication for the entire summer. Both herds had access to bahia grass pasture and woodland for forage. In South Alabama, goats typically do not survive the summer unless they are wormed. In late September fecal samples were taken: The goats on sunn hemp had very few worm eggs present. Each goat had gained 10 - 20 lbs. over the summer. The kidding rate of each doe doubled from 1.2 kids in 2009 to 2.1 kids per doe in the fall of 2010. Documentation and observations from two veterinarians proclaimed the goat herd on sunn hemp to out perform the goat herd on full feed but no sunn hemp.    

Synchronizing Goat Breeding with Sunn Hemp


For the second year now we at Petcher Seeds have grazed goats on Sunn Hemp. Thirty five does and three bucks were control grazed on Sunn Hemp starting June 1, 2012.  On June 10 the does became receptive and, starting 146 days later, every doe gave birth within the next 10 days. A total of 65 kids were born at this time. The birthing rate was 1.9 kids per doe.  The birthing period, covering only a 10-day span, greatly reduced our labor and stress of the kidding season. It will also help in having the herd of weaning kids ready for market at the same time.



Sunn hemp is also excellent for wildlife:  Deer will walk a mile for it. In fact, if you have sunn hemp with deer in the area, you will not be able to keep them out of it. The new leaves of sunn hemp are 30 percent protein. This gives the protein to deer while the bucks are in antler development and also while does are carrying fawns. Late summer, the sunn hemp will also greatly boost milk production of the does with fawns. Both turkey and quail find good cover and other food sources, such as grasshoppers, in sunn hemp. Rabbits abound in sunn hemp as they find it a nutritious food source and cover.  


Does Your Deer Plot Need Lime?

Does Your Deer Plot Need Fertilizer?

Does it Provide Nitrogen,Phosphorus and Potash for the Winter Food Plot for the Entire Winter?

Does it Provide Cover for Turkeys, Quail, Rabbits and Deer?

Is it Drought Tolerant?

Does it Attract, Feed, Grow, and Keep Your Wildlife?

Does it Suppress Nematodes?

Does it Suppress Unwanted Weeds?

Does Your Summer Food Plot Add 5 Tons of Organic Matter to Your Soil?

Our Summer Sunn Hemp Plot Does It All!



(Left) Dr. Steven Petcher, in Fruitdale, for several years has been using Sunn Hemp to draw deer into his fall food plots. (Right) Peter Gail enjoys the pleasure of bowhunting over Sunn Hemp.  

Starting in September, Sunn Hemp does not grow as tall as when planted earlier. However, many deer hunters are planting Sunn Hemp in September at a 7 - 10 lbs. per acre mixed in with their early fall winter deer food plots. The young, tender, high protein Sunn Hemp dynamically attracts the deer. The beauty of the Sunn Hemp is that it only gets 2 – 3 feet tall and you can still see the deer. Twenty eight degrees will terminate the sunn hemp. The Sunn Hemp planted late does not have time to do much improvement to the soil. However, strips of oats with Sunn Hemp did stay greener throughout the Winter than strips of oats with no Sunn Hemp.  


AU Golden Sunn Hemp and Quail Haven Soybeans mixed is “The Premier Quail Food Plot.” The Sunn Hemp will grow rapidly and give the quail plenty of cover and plenty of insects for the quail to feed on. The Quail Haven will produce between 500 and 1,500 lbs of small soybeans for the birds to feed on over the winter. The AU Golden will produce between 1,000 and 1,500 lbs of seed per acre.  

Ten lbs. of Sunn Hemp and 10 lbs. of Quail Haven Soybeans per acre can be mixed and planted together, as seed are the same size. They can be drilled or broadcast and lightly covered. Plant anytime after April 15, on a fairly well prepared seed bed. Soybean inoculant is recommended. Fertilizer is not necessary but will help on poor soils. Leave the plot standing over the Winter. Twenty-eight degrees will kill the Sunn Hemp and soybean vines. The soybeans have hard seed coats and will provide feed over the winter.  A light discing the following Spring will allow both Sunn Hemp and Quail Haven soybeans to germinate and grow the following year. Beside providing cover, food, drawing and keeping your wildlife, this mix will greatly improve your soils.  



Only at Petcher Seeds do you stay on the phone for 3.5 hours fixing computer problems, then go out to help the boss search for a baby fawn. After a little searching, we found the day-old fawn and gently placed her back in the Sunn Hemp field where she was born and would be safe. Very shortly we saw her mother cross the road to return to her fawn. God’s beauty is all around us everyday. His creation is such a blessing.

As most of you know already, besides being a nutrient rich forage, Sunn Hemp provides excellent cover for all wildlife. Especially rabbits, quail, doves, turkey, and of course deer.

Each year at Petcher Seeds we have a number of fawns born in our Sunn Hemp patches. Because we graze our goats in the same fields, we are able to see the fawn frequently.

If by chance you are bush hogging your Sunn Hemp patches please watch out for the fawns!



A Golden Opportunity: Harvest Corn - Follow with Sunn Hemp - and then Wheat

One of the major keys of cover crops is finding the window of opportunity that fits your farm. Placing Sunn Hemp right after corn harvest is a golden opportunity. This window may be tight for many farmers as the Sunn Hemp should be planted by August 25. Sunn Hemp is day-length sensitive. Sunn Hemp planted after Aug. 25 will only get 2 - 3 feet tall.  Some cover crop growers are harvesting their corn in the afternoon and then planting a few acres of Sunn Hemp early the next morning. Waiting until the entire corn crop is harvested may narrow or even close the window of opportunity.  

Sunn Hemp in 60 days is typically 6 feet tall and, being a legume, provides 100 lbs. of Nitrogen and brings up 20 lbs. of Phosphorus and 80 lbs. of Potash from the subsoil. It also produces four tons of organic matter as well as suppressing nematodes and weeds. It is excellent, particularly on suppressing Palmer Amaranth.   

A golden opportunity is to fit Sunn Hemp after corn but before wheat. Wheat responds very well to Sunn Hemp and the Nitrogen and other benefits that it provides. Some wheat growers are producing their best wheat following Sunn Hemp. They are reducing the Nitrogen by 1/3 - 1/2 of their normal rates.  


Mallory, daughter of Garry and Teresa McNeil of Fruitdale. This photo was taken during a three-week drought. When most vegetables were doing poorly, however, this garden still produced squash, tomatoes, and other vegetables.

Make the worst garden the best with Sunn Hemp and Sodbuster Radish. Anytime you do not have a crop on your soil, fill those gaps with Sunn Hemp or Sodbuster Radish. Sunn Hemp in the Summer followed by Sodbuster in the Winter will totally rebuild your soil and dynamically improve your next garden.