Chickens · Food Garden · Homesteading · Off Grid · Soil care

Green Manures: Cover Crops & Green Forage

I was actually researching green forages as alternative feed for chickens when I noticed there is a large overlap between green forages and green manures. Seeing that nothing is happening in the garden for most of winter I decided to look into green manures a little bit more in detail to grow during the winter months as a cover crop. Here is what I found and thought that I should share 

Green manures, also known as cover crops, are grown as part of a good soil management and crop rotation scheme.
Sunflower field
Sunflower field 
Helianthus annuus (a green manure) 
Flickr upload bot
Green manures fall into two main categories: Legumes (Nitrogen Fixers) and Non-legumes. The legumes add nutrients to the soil by converting atmospheric nitrogen (N2) to bio-available ammonia (NH3) in the soil. This is performed by bacteria, Rhizobia spp., that lives symbiotically with the plant contained in root nodules. Non-legumes are not able to fix nitrogen, but accomplish all the other tasks of green manures.
Green manures provide the following services:
✓ Replace or hold soil nutrients
✓ Improve soil structure (loosen hard soil and soil conditioner)
✓ Add organic material to soil
✓ Suppress weed growth
✓ Supports the soil community (decomposers)
✓ Act as Insectaries (shelter and house beneficial insects)
✓ Mulch soil & prevent wind or soil erosion
✓ Increases soil water retention
✓ Keeps soil temperatures warm
✓ Flowers attract pollinating insects
✓ Some have inhibitors that prevent soil disease & pest build-up
Most vegetable gardens are dug over and the bare soil left as is for the remainder of winter. This may lead to soil and nutrient loss due to leaching and erosion. Green manures prevent this and it not like the plot is used for anything else…
Although legumes add nutrients to the soil, they are generally slow growing in autumn and provide less organic material (or biomass) than non-leguminous plants. Therefore it is preferable to use a combination of both – to get the best of both worlds.
Some green manures have very deep reaching roots that grow into the subsoil and harvest nutrients inaccessible to other plants – for this reason they double dig.
Generally you can grow green manures in the warm or cool seasons. This means that the tilling (cutting down and working into the soil) of the summer manures occurs during autumn or winter frosts kills off the manure and winter manures are tilled before spring planting. The plants are usually tilled before flowering to prevent seed formation keeps the manures from becoming weeds. Green manures are tilled a month before sowing any new vegetables to ensure that they have broken down and will not burn the following crop.
Lacy Phacelia, Phacelia tanacetifolium
Lacy Phacelia
Phacelia tanacetifolium
Curtis Clark
Here is a table with most of the well-known and widely used green manures (those that aren’t in the table have been provided with links below). An all-in-one resource :
Green manures information table, alfalfa, buckwheat, clover, fava beans, fenugreek, lupin, mustard, oats, phacelia, rye, soybean, sunflower, sunn hemp. trefoil, tyfon, velvet, bean, vetch
Green manures information table

On that note, some of the beans and peas can be left to crop as they are easy to collect and will prevent them from going weedy. Some of the legumes are susceptible to soil borne pathogens and should not be followed by another legume crop, such a susceptible crop would be Vetch.

Sunflowers produce an allelopathic compound that suppresses weeds and other plants growing nearby (good to keep in mind not to plant among other vegies!) Vetch needs to be cut at flowering for it to reach its full biomass and N2-fixing capabilities.
Alfalfa and sunflowers are drought resistant and can grow in more arid regions. Alfalfa and clover flowers attract a lot of bees! Rye and oats are easily killed by cool conditions (can easily be frost-killed), therefore winter rye and oats cultivars need to be grown in winter (those are featured in the table).
I am specifically going to mention Alfalfa, because of its green forage (alternative feed) potential for chickens. I will cover green forages for chickens in another article (coming soon!). Alfalfa has a very deep rooting system and can grow to 4-9 meters tall. After the formation of its crown, it can withstand continuous grazing. It is a perennial that can live for up to 8 years and the flowers are very attractive to bees (used in bee pasturages). Alfalfa is not readily pollinated by western honey bees as the anther (structure with pollen) strikes the bee on the head when it collects honey. Bees don’t like this and learn to steal nectar from the side of the flower – thus the alfalfa leaf cutter bees are provided to pollinate alfalfa. I do not know whether this applies to African honey bees, but hopefully this will limit the seed-2-weed part. Also alfalfa seeds fail to germinate in already existing stands due to auto-toxic compounds.
Megachile rotundata, alfalfa leafcutter bee, alfalfa, medicago sativa, flowers, pollination
Alfalfa leafcutter bee
Megachile rotundata
Therefore, alfalfa is drought tolerant, can grow in the winter and provides green forage to chickens. It has since gained a permanent spot in my vegetable garden and pumpkin patch.


Those not covered in the article you can get full details about here:
  1. Ryegrass, arugula, buckwheat, field peas, forage radish, forage turnip/rape, hairy vetch, mustard, oats, red/white clover, sudan grass, teff ,reed canary grass, rye, wheat
  2. Black oat, cereal rye, crimson clover, cowpea, field mustard, lablab, oilseed radish, pea, pigeon pea, sorghum, sunn hemp
  3. Cowpea, jackbean, lablab, pigeon pea & velvet bean
  4. Cowpea, field pea, Vetch and clover
  5. Sunflowers

14 thoughts on “Green Manures: Cover Crops & Green Forage

  1. Baie dankie, Whiskerflowers vir die uiters handige tabel! Ek het vanjaar alfalfa rondom al my beddings gesaai, met die hoop dat dit ‘n skans sal vorm teen gras wat die beddings indring. Sal maar moet sien hoe effektief dit gaan werk. En natuurlik ook later kos vir bye sal veroorsaak. Ek hoop om in September ‘n korf in my stadstuin op te sit. Ek het ongelukkig nie hoenders nie, maar die gesnyde lusern sal sekerlik goed te pas kom in die komposhoop.

    Liked by 2 people

    1. Haai daai! Dis ‘n groot plesier – alfalfa is ‘n baie goeie plant om in die tuin in the bring, hy het baie voordele vir die gesondheid van die grond, lok goeie goggas en lyk mooi ook. Jy kan hom redelik gereeld snoei om hom netjies te hou en die komposhoop sal verseker baat vind by sy byvoeging! Ons wou ook al ‘n bye korf kry, maar met die munisipale reëls ( bladsy 72) en die bye vereeniging se vooie wat dit moeilik maak, het ons toe nou teen dit besluit. Ek plak sommer die goed hieronder vir Johannesburg as jy dalk daarvan wil weet:

      “Requirements for keeping of bees
      145. (1) No person may keep bees on any premises unless –
      (a) that person is the holder of a permit authorising that activity; and
      (b) every bee hive is situated –
      (i) a minimum of five metres from any boundary of the premises; and
      (ii) a minimum of twenty metres from any public place or building used
      for human habitation or from any place used for the keeping of
      animals, poultry and birds;
      (c) the bees are kept in an approved bee hive; and
      (d) the bee hive is –
      (i) kept in an area inaccessible to children and animals;
      (ii) …… (Section 145(1)(d)(ii) deleted : Notice: 5319: 5/12/07, PG 347)
      (iii) supplied with a source of drinking water within five metres of the hive.
      (2) No person may dump or deposit any garbage, compost, grass cuttings or
      manure within five metres of any bee hive.
      (3) Bees must at all times be kept strictly in accordance with the Council’s guidelines
      for the keeping of bees.
      (Section 145 (3) inserted Notice: 5319: 5/12/07, PG 347)”

      Die ‘approved bee hive’ kan ‘n mens net vanaf die vereeniging koop (…

      Groete en baie geluk met die tuin uitbreidings! 😉

      Liked by 1 person

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