Type
Legume            when to sow              comments  
afalfa              spring                 perennial, deep-rooted, needs drainage, neutral pH.
beans, fava         spring or autumn       annual, edible.
beans, soy          spring                 annual.
clover, alsike      spring to late summer  tolerates wet acidic soil.
clover crimson      autumn                 winter annual.
clover, ladino      spring to late summer  tolerates traffic, wet or droughty soil.
clover, red         spring to late summer  perenial, good phosphorus accumulator.
clover, sweet       spring to summer       needs good drainage and neutral pH, yellow clover tolarates dry conditions
clover, white dutch spring to summer       perennial tolerates traffic.
cowpeas             spring                 annual, drought resistant. 
hairy indigo        spring                 needs warm, well drained soil, resist root knot nematode.
lespedeza           spring                 good for restoring eroded, acidic soil.
lupine,             spring                 tender annual, good biomass producer.
(white or blue)
pea,                spring or autumn       annual, best combined with grain crop.
(field or austrian)
trefoil, birdsfoot  spring                 comparable to alafalfa but tolerates poor soil.
vetch, hairy        spring to autumn       best combined with rye, good biomass producer, winter-hardy.

non legume
barley              spring or autumn       needs pH 7-8.
brassicas           spring to autumn       fast growing, cool season do not allow to set seed,
(kale, radish, mustard...)                                     unless you want it to spread...
bromegrass, smooth  autumn                 cold hardy winter cover crop.
buckweat            spring to summer       tender good smother crop, phosphorous accumulator.
.millet, pearl       spring to summer       fast-growing warm-season smother crop, tolarates low pH.
oats                spring to autumn       tolerates wide range of pH, avoid heavy clay, good nurse crop for legumes.
rye, winter         autumn                 suppresses weed growth whenturned under.
ryegrass, annual    spring to summer       widely adapted rapid grower.
sorghum             spring to summer       tolerates poor drainage, rapid biomass producer in hot weather.
wheat,              winter late summer     needs pH 7-8 and good fertility.