Best adapted cover crops for S.California

I'm just starting to experiment with cover crops in my gardens in coastal California. It does not freeze here, and many things grow whenever there is enough water. I've noticed some of the weeds that have come up after rain in the yard are growing more lush than the seeds I've intentionally planted. Since plants are plants, I'm planning on harvesting seeds of the best of them for replanting next year in the veggie patches.

The better 'weeds' seem to be:

California poppies - fast growing, totally herbaceous, and pretty.
Malva - fast growing, deep rooted. Can get too large, but it can be removed at that time.
Lamb's quarters - fast growing, can get big
Nettle - shorter species. fast, lush, but has stinging hairs. Not sure I want more of this
Lupine - legume, lush, both attractive and fragrant. One of my favorite plants. Not sure I'd ever be able to trim it.
Calendua - fast growing, easy to germinate, attractive. Stays smallish.
Melilotus - legume, not vining, not too large. Does well here.
Sonchus - upright dandelion type. Very lush, tap root, easy to control


Planted seeds for cover crop - mostly left over garden veg. seed from previous years:

Buckwheat - seems really good. Herbaceous, straight growth, easy to control
Lentils - from the grocery. Legume, inexpensive seed, seems easy to control. Cute little thing
Flax - germinates, slight plant, but has pretty blooms
kohlrabi - slower to grow, but are surviving. Good to eat
arugula - vigorous, good germination, one of the best of the old seeds. grows fast
bird seed/millet - seems to grow well, but the birds liked the seed.

I also had planted in the cover crop seed mix, but didn't do well. Red clover, alfalfa, broccoli, lettuce, and a few other things that either didn't germinate well, or didn't survive.

Between the cover crop plants in the beds, I've interspersed transplants of beets, chard, kale, bok choi, tomatoes, and chilies. And onion and garlic sets. All are doing pretty well, though as I keep harvesting the greens, the cover crops are perhaps shading some of them too much and affecting their growth. Might have to do some trimming soon.

I am amazed at how fast the bok choi grows. I might have to plant more of that to get seed and use that as part of the adapted cover crop mix too.

Anyone else using non traditional species as cover crops in a Mediterranean climate?

Between the cover crop plants in the beds, I've interspersed transplants of beets, chard, kale, bok choi, tomatoes, and chilies. And onion and garlic sets. All are doing pretty well, though as I keep harvesting the greens, the cover crops are perhaps shading some of them too much and affecting their growth. Might have to do some trimming soon.

It's been just over a week since posting the above. We've had some rain, and some nice sunny weather and everything is growing well. Today I went out to trim around some of my 'crop' plants planted in between the cover crops. The cover crop varieties (plus some weeds) are definitely more vigorously growing than the plant starts set out in between. The chilies, which I've put out quite a lot, needed the most help. Some were even hard to find. They are healthy, but just can't compete with things selected for rapid growth. So with scissors I just cut off the over-arching covers that were near. I expect I'll have to do this again. Perhaps as summer comes, I'll want to cut the covers to the ground and deep mulch with other stuff.

The bok choi continues to be an animal. It is one of the fastest growing things out there. Definitely will let some go to seed and add it in my personalized crop cover mix.

I love the idea of planting lots of things for optimal capture of photosynthetic/carbon products. It will take more work, but as long as my food plants don't suffer, I'm willing.

Hello Rue,
Same here, I have no frost, so we can have similar experiences. I can see the sea, but I am at 500m high.

Well, cover crops are usually more for uncultivated places, and your crops should cover enough.

I have mostly the same as you mention, except the poppy, I have the european ones! So, red and purple.
I have lots of sonchus, edible small one, and more bitter and very big endemics from the Canary. Good animal food anyway.
I have some more, like tedera, a wild legume, bitumina bituminosa I think in latin.
I also leave a wild local oat. I control other legume because they climb....
I have a lot of an oxalis, covers great but extend too much.

A very good edible cover is the new zealand spinach, or tetragona. They spread and are not so high.
Another one is nasturtium. They grow all winter here. A real weed, but not spiny and produce loads, and edible and medicinal, so great weed!

I grow sorgum because of its great rooting and perenial type, also coix lagrima jobi, for cereal.
And cajanus cajan as a perenial legume. 3 years.
Lima and lablab and runner beans are great too.
No frost means a lot of diference...

I also have a lot of Oxalis, both pes-capri (from persistent bulbs) and an annual type. Love the pes-capri - it can take over local orchards and is pretty. And easy to pull, though it will come up again next year. But it creates lots of bio-mass.

There are also lots of Mediterranean grasses here - mostly oats and various brome grasses. Some thistle too, though I do try to remove those before they bloom.

Vicia villosa (hairy vetch) does well here, but can become a problem, so I'm steering clear of it. We used to have bindweed when first here, but it seems to have disappeared for some years now. I never even noticed.


Because I think our rain for the season may be over, I've decided to chop- drop the cover crops now, and cover everything with deep mulch to conserve what moisture is still in the soil. I had planted chilie pepper starts between the cover crops, and they were not as vigorous as the 'weeds', but I did find almost all of them and they look pretty good.

I think I'll also drop most of the cover crops between other things growing now too. They served their purpose, and while more work dealing with them, the soil will be better because of them.

I learned it's best not to toss in the seeds of things I like to eat - it's more work to 'weed' around things I want to save. So no more kohlrabi in the mix, lol.

Here are the keepers:

Lamium - small, drought tolerant sage. Calif native.
Arugula - vigorous grower, stays low, germinates well
Small nettle - hate the stinging hairs, but it's already in the soil and it grows very fast
Bird seed - inexpensive, with both grasses and sunflower seeds
Lentils - delicate plant, but a legume. Did not innoculate. Cheap seed.
Calendula - pretty, germinates well, drought tolerant
Cal poppy - same as calendula
lamb's quarters and malva - natural weeds here

Didn't work:
Alfalfa and red clover - neither germinated. Old seed, or got eaten
Linum/flax - germinated, but not much growth for a cover crop. I left some to bloom
Lettuce - some germation, but old seed, and not very vigorous compared to others
Kohlrabi - germinated and grew, but hard to weed around since I want to eat them

To try, probably next fall:
cowpeas/black-eyed peas - just purchased some at the store.
Collect seed from whatever hits my fancy to try. Want more flowers in the mix.
Rudbeckia/black-eyed susans. Do well here. I think I have some seed someplace.

What, no mustard?

This time year, there can be entire hillsides covered in yellow mustard blossoms. I understand it was introduced by the Spanish padres in the 18th century and has pretty much naturalized in most of the state.

That is sooo similar!
My main ones:
The links have photos, and you can see the latin name in the links.
leguminacea
http://www.floradecanarias.com/bituminaria_bituminosa.html
this oone grows into trees if I do not control...
http://www.floradecanarias.com/lathyrus_tingitanus.html
http://www.floradecanarias.com/medicago_lupulina.html
http://www.floradecanarias.com/melilotus_sulcatus.html
http://www.floradecanarias.com/melilotus_indicus.html

fumaria covers super good
http://www.floradecanarias.com/fumaria_muralis.html

Look like mustards:
Relinchon, that was used for soups and animals
http://www.floradecanarias.com/hirschfeldia_incana.html
also for soups, it has no radish root:
http://www.floradecanarias.com/raphanus_raphanistrum.html

I live in Los Angeles county, so my experience should be relevant.

I sew a cover crop in October or November --- a cool season mix from Peaceful Valley: http://www.groworganic.com/soil-builder-mix-raw-lb.html

It grows like crazy all winter. Right now, the oats, peas and vetch and the rest are a jungle out there --- some of it is 5 feet tall. I'll crop and drop it a little bit at a time over the next month or two as I need space to plant the next wave of veggie and fruit seedlings that are ready to go into the ground. I'll gather seed from some of it for use next fall, but I like to buy a new batch of seed (10 lbs. or so) every year because I also want to buy the bacterial inoculant that you need in order for it to fix nitrogen. I end up using about 25 lbs of inoculated cover crop seed, sewing it throughout my orchard of 50 fruit trees. I simply broadcast it into the mulch and rake it in. It always germinates.

In the summer, sweet potatoes, summer squash, watermelon, cantaloupe, cucumbers, and other vining crops tend to serve as a cover crop. Sweet potatoes take over the world if you're not attentive. I'm forever tossing a vine from this or that back into the scrum of stuff that wants to get off the reservation. You've got to be attentive, or vines will cover your smaller "stationary" veggies like salad crops and such. Even tomatoes go crazy in our climate (as you know)—I've currently got 20 or so volunteer tomatoes out there right now. My food forest floor is covered with some growing thing 90% of the year, capturing that solar energy and converting it to food or cover-crop mulch, and pumping root exudates into the soil to feed the web.

John Elliott wrote:What, no mustard?

This time year, there can be entire hillsides covered in yellow mustard blossoms. I understand it was introduced by the Spanish padres in the 18th century and has pretty much naturalized in most of the state.

Yes, lol, mustard... I also have a hillside of it (Brassica campestris), blooming right now. Besides the grasses, it's my most common weed. It's also a weed that comes up in my garden beds. I did think of using it as a cover crop because it is so successful. It grows fast, and is easy to control. But... it looks too much 'like a weed' to me. I know that's unfairly subjective, but I've recently realized I want my patches of cover crops (some of which are in the front yard) to look like meadows, and this mustard is just too rank to fit into that scenario. It can grow to 6 feet tall here in the right circumstances.

There is a smaller mustard that also grows here that is more petite in leaf morphology and size. It's probably not as effective, but sometimes aesthetics count. I don't know the species, but I've got a few of them segregated and plan to collect their seed for next year.

Wild radishes also grow here in town in shades of pink, yellow, white, and hybrid colors all in between. It's a pretty thing, growing to 2-3 feet max. But I hesitate to introduce a new very successful weedy species to the property. I might collect some seeds of it when they are ready however.

Xisca Nicolas wrote:That is sooo similar!
My main ones:
The links have photos, and you can see the latin name in the links.
leguminacea
http://www.floradecanarias.com/bituminaria_bituminosa.html
this oone grows into trees if I do not control...
http://www.floradecanarias.com/lathyrus_tingitanus.html
http://www.floradecanarias.com/medicago_lupulina.html
http://www.floradecanarias.com/melilotus_sulcatus.html
http://www.floradecanarias.com/melilotus_indicus.html

fumaria covers super good
http://www.floradecanarias.com/fumaria_muralis.html

Look like mustards:
Relinchon, that was used for soups and animals
http://www.floradecanarias.com/hirschfeldia_incana.html
also for soups, it has no radish root:
http://www.floradecanarias.com/raphanus_raphanistrum.html

We have some of the same species here too. Judging from the photos of others I'm not familiar with, I suspect you might get more rain that we do. We have species of Fumaria (or at least species in the same family) in more moist parts of the state, but not very close to here. A lot of your Canary Island palms are planted locally too. Beautiful things.

We have Raphanus raphanistrum locally, and in spring I've tried the roots, but they are slender and very strong tasting.

Marco Banks wrote:I live in Los Angeles county, so my experience should be relevant.

I sew a cover crop in October or November --- a cool season mix from Peaceful Valley: http://www.groworganic.com/soil-builder-mix-raw-lb.html

It grows like crazy all winter. Right now, the oats, peas and vetch and the rest are a jungle out there --- some of it is 5 feet tall. I'll crop and drop it a little bit at a time over the next month or two as I need space to plant the next wave of veggie and fruit seedlings that are ready to go into the ground. I'll gather seed from some of it for use next fall, but I like to buy a new batch of seed (10 lbs. or so) every year because I also want to buy the bacterial inoculant that you need in order for it to fix nitrogen. I end up using about 25 lbs of inoculated cover crop seed, sewing it throughout my orchard of 50 fruit trees. I simply broadcast it into the mulch and rake it in. It always germinates.

In the summer, sweet potatoes, summer squash, watermelon, cantaloupe, cucumbers, and other vining crops tend to serve as a cover crop. Sweet potatoes take over the world if you're not attentive. I'm forever tossing a vine from this or that back into the scrum of stuff that wants to get off the reservation. You've got to be attentive, or vines will cover your smaller "stationary" veggies like salad crops and such. Even tomatoes go crazy in our climate (as you know)—I've currently got 20 or so volunteer tomatoes out there right now. My food forest floor is covered with some growing thing 90% of the year, capturing that solar energy and converting it to food or cover-crop mulch, and pumping root exudates into the soil to feed the web.

I'm a bit to the north of you and we just didn't get much rain this year, and probably won't get much more so besides the cover crops, many of which I'm dropping now, I'm going to deep mulch.

Thanks for the link to the cover crops. I coincidentally just ordered some blueberry plants from them. I think for now and next year I'm set for seeds. The plan is to use old seed still in the fridge, as well as new weed seed collected from the property this year, plus inexpensive grocery store seed, and the stuff that just comes up on their own.

I have not been using inoculate for the legumes I've planted and I know they are not as efficient in N-fixing because of it. That's why I want to grow more of the ones already on the property that flourish. The Lupines on one small slope are going berserk, and the Melilotus indicus (whose seed I've collected and broadcast before) is lush this year, even with limited rains.

I'm planning to grow a number of winter and summer squashes this year but probably not melons. Because of the drought, those will have to suffice for the vine component.

Yes, tomatoes do very well here. They can almost be totally dry-farmed, and I believe in local history, before reservoirs, they were commercially. And when they are grown without additional water, they are exceptionally good. I have some in, and the first fruits are about an inch in diameter. When we did get some rain, I diverted much of the flow from one downspout into that sunken bed, so I hope the soil is storing enough.

Does anybody have a recommend for a shade cover crop?  My urban raised beds get a ton of sun in the summer, but in winter get no sun at all.