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Global Sunn® (Sunn Hemp, Crotalaria juncea)

Download Global Sunn Planting Guide


Global Sunn® 

Tech Sheet


High Value Cover Crop and Rotation/Break Crop

Fast-Growing Warm Season Legume

- Organic Growers - Roll down for weed suppression

- Non-GMO

- Vegetables - Weed suppression and N-Fixation

- Following Winter Wheat Harvest - Weed suppression

- Sugar Cane - Weed suppression, N-Fixation during fallow period between old/new crop

- Summer grazing - during young succulent stage. High protein leaf re-growth during summer  

- Goats thrive on Global Sunn®

- Fallow soil in warm conditions




Vegetable Break Crop

Global Sunn® is a favorite crop to plant between cash crops for vegetable growers. It scavenges remaining soil nutrients, produces copious amounts of N and other nutrients through the biological activity on the roots, producing huge nodules of N, which is readily available for vegetable crops that follow.


Global Sunn® is also known to suppress reniform and root cyst nematodes, which do damage especially to crops grown in sandy and sandy/loam soils. Soil stays cooler with Global Sunn® planted, and weeds are suppressed by the dense shade. 


Terminated Global Sunn® stands can be mowed, flail mowed or rolled down and sprayed to control. The large amount of biomass can be incorporated or left on the surface to decompose, depending on cultivation practices and circumstances.




Rebuilding Soil

Global Sunn® is known around the world as one of the best species (Crotalaria juncea) for rebuilding poor soils. In fact, it seeks out soil nutrients remaining after a crop is harvested. 


Sometimes it requires a starter fertilizer, but once Global Sunn® starts growing, it produces significant amounts of nitrogen (N), up to 140 lbs / acre according to university research. 


The biomass is also significant, and can reach 5,000 lbs/acre in good growing conditions. This biomass can be incorporated into the soil as fuel for beneficial soil microbes, or can be left on the surface to serve as a soil cover.




Small Grain Cover Crop

Global Sunn® makes an ideal cover crop following small grains, where there is no double-cropping, such as with soybeans. Global Sunn® germinates and emerges quickly, given adequate moisture. Once established, as a tropical legume, Global Sunn® thrives in hot weather and tolerates dry soil conditions.


In soils with poor fertility, Global Sunn® generates significant N and other nutrients as part of its growth habit.


Global Sunn® terminates with the first freeze. Or, if flowers appear before the first killing frost, it can be mowed, flail mowed, or rolled down and sprayed with an appropriate herbide.


Global Sunn can be planted along with other cover crops, such as cover crop radishes, sorghum sudangrass and other species. In these cases, Global Sunn® grows quickly, while species like radish are vigorous enough to get established.


Then, following the first killing frost, when Global Sunn® is terminated, plenty of light triggers vigorous growth of cover crop radishes to absorb and store the N produced by Global Sunn® through the winter. When the radishes die following a few consecutive nights of temperatures in the mid-teens (degrees F), the nutrients are stored over winter, then released again to the soil when temperatures warm in the spring.




Attracts Wildlife 

Wildlife, including deer, enthusiastically prefer Global Sunn® to other plants, including corn and soybeans. 


In addition, once killed by freezing conditions, standing stalks of Global Sunn® create an ideal bedding venue for deer. They can hide amidst the standing stalks, while easily creating a dry mat from those same stalks for sleeping.




Weed Suppression Following Silage

Dairy famers harvesting corn for silage face an increasingly troublesome problem with herbicide resistant pigweed, Palmer amaranth, which grows rapidly, produces enormous numbers of seed, and can grow as large as a good-sized Christmas tree. Global Sunn® brand sunn hemp is one of the only plants capable of out-competing pigweed's rapid and aggressive growth. 


This application will not apply to northern dairy farmers due to the short planting window. Global Sunn® requires eight weeks in warm conditions to provide maximum benefit. The concept may be worth considering for dairy farmers in warmer growing zones.



Land Reclamation

Few plants can equal Global Sunn® to help restore disturbed topsoil, such as at construction sites, mined areas, and other places where a return to healthy soil is an objective, once the work is done. 


Global Sunn® produces nitrogen (N)  and additional nutrients that other plants can use through the cooler weather. Rejuvenating spent soils is one of the primary reasons Global Sunn® is used in other parts of the world, where fertilizer is expensive and difficult to apply. The combination of up to 140 lbs/acre of plant available N and up to 5,000 lbs/acre of biomass is the reason Global Sunn® brand sunn hemp (Crotalaria juncea) has been heavily used for centuries. 




Small Animal Forage

No animal thrives on Global Sunn® greater than goats. Global Sunn® is also a good fodder for sheep and chickens. In addition to deer being attracted to it, as are wild turkey and quail. 



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Highest Quality, Lowest Cost

Global Sunn® seed is harvested and cleaned like no other sunn hemp brand, providing assurance of clean seed and high germination. That's why we call Global Sunn® the best quality sunn hemp seed you can get. What's more, Global Sunn® costs less too!

Winter Wheat producers who do not plan a double crop can use Global Sunn® as a soil building cover crop following harvest.

Vegetable growers know Global Sunn® as a great break crop between cash crops. It suppresses reniform and root knot nematodes, scavenges and fixes nutrients and grows up to 6 feet in 60 days in good conditions–adding from 2.5 to 4 tons of biomass per acre.


As a legume, Global Sunn® replenishes soil Nitrogen. Within 60 days it typically fixes over 100 pounds of Nitrogen. Added N has been measured as high as 140 pounds, which is exceptional. Global Sunn® also grows very deep roots and brings up approximately 10 pounds of Phosphorus and 80 pounds of Potash from the subsoil.

Corn silage is harvested while weather is still warm. Sometimes the worst happens: Here comes herbicide resistant Palmer amaranth, or pigweed. It can be a big problem. Global Sunn® is one of the only plants that can out-compete pigweed in terms of rapid growth. This means pigweed can potentially be shaded out. It’s not a silver bullet, but another tool in the box for dairly farmers to use when combatting this noxious weed.

UF - Crotalaria juncea Management of Nematodes & Soil Fertility

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