Companion planting with Asparagus

Hi all,

I established a long asparagus bed this year. It has 30 crowns of the "Connover's Collosal" cultivar, planted in a ridge of sand-compost-topsoil. After an initial battle with the field slugs the plants seem to be doing okay and there are several large ferns - most crowns have at least one spear that has leafed up. I've been weeding the bed to give the asparagus the best start, with the least competition, but I can't help but think that this is both wasted space and unhelpful for the soil itself. Nature abhors a vacuum, as they say.

I wonder if anyone can recommend a good cover crop or companion planting scheme that I can grow between or on top of the asparagus? I imagine it would want to be a relatively light feeder, and shallow-rooted to not disturb the crowns. I have thought about sowing mustard or alfalfa as a green manure/micro-salad crop but there might be better suggestions.

TIA

The first plants that I thought of were strawberries.

Some other good choices would be comfrey, and the Aster family, like marigolds and nasturtiums.

What makes you say comfrey, Anne? I would imagine that their long, spreading roots would cause mayhem with the asparagus crowns.

I too have thought about strawberries. They would quite easily cover the bed and provide a crop. I hesitated as I know they can be heavy-ish feeders, the cultivated varieties, anyway.

Nasturtiums are a good idea as I suspect that they might deter asparagus beetle (I've not had any issue with those yet but I know many do). Marigolds, which I plant sporadically around the garden, are likely to have this benefit too - but I like to eat these less. The disadvantage with both of these plants is that they will die over the winter and the ground will be exposed for several months.

Thanks for your suggestions

Luke said, "What makes you say comfrey, Anne? I would imagine that their long, spreading roots would cause mayhem with the asparagus crowns.

I have never grown comfrey so I don't know.

Something about your pictures said comfrey borders ...

Luke, there's been a bit of discussion about this in the past, see these threads for some ideas:

https://permies.com/t/114916/Black-Eyed-Susan-Asparagus

https://permies.com/t/161987

https://permies.com/t/157612

https://permies.com/t/141673

I have the same thoughts as you - nature abhors a vacuum and weeds will expand to fill the soil available and then some!

Thinking about Asparagus and it's growth habit: Once established it has deep roots (see here for some relative root depth information). It is normally planted a little deep, so that we get partially balnched spears and some extra protection from winter weather I guess. The plant is supposed to die down in winter - I have mine in the polytunnel (Argenteul early and Connovers colossal grown from seeds) and they don't tend to die back much over winter. I get a little grey mould developing, so cut them back in late winter, but they seem to just keep on going! They need quite a bit of feeding in the early years - it took mine several years to get to cropping size, but they do pretty well for me now.
My conclusion was to try and find something that was shallow rooting or sprawling and relatively low growing not minding shade. If it died back in winter also, then both plants could be mulched with seaweed (in my case) or other bulky nutritious mulch over winter. Martin Crawford suggested milk vetch (Astragalus glycyphyllos) so that's what I planted. It's been a bit bigger than I expected, but sprawls around without seeming to do the asparagus any harm, maybe it succeeds in fixing nitrogen to help feed the soil, I'm not sure. It does grow quite a bit of bulky biomass which I chop and drop a bit and also dies back over winter enabling mulching if desired. Being a perennial it comes back year after year and has insect attractive flowers.
.....I now also have kale, parsley, strawberries, garlic, docks, chickweed and leaf beet coming and going around the asparagus. All auto-mulched with grape leaves every winter! I guess the thing is to try and avoid more competitive weeds like couch grass or nettles and chop and drop anything else that gets to be a nuisance.
Good luck -your set up looks really good, you've put some hard work in there. I'm thinking of trying some outside myself, if I can just find a nice sheltered spot from the wind.....

Nancy Reading wrote:
https://permies.com/t/114916/Black-Eyed-Susan-Asparagus

https://permies.com/t/161987

https://permies.com/t/157612

https://permies.com/t/141673

Thank you for the links! I did have a search before posting but I missed some of those.

My crowns are planted reasonable deep - about 6". The mound is dressed with very dark compost and that seems to help with heat and moisture retention. I have a large bucket of organic blood, bone and fish meal and I'll give the crowns a feed with that towards the end of summer, when it gets a bit wetter and they've made a dent in the nutrients in the compost.

Interesting that you mention milk vetch. I have left some birds foot trefoil that self-set on the mound which ought to behave quite similarly - fixing nitrogen, sprawling with shallow roots. Leaving that to spread might be enough for the moment, followed by a fresh compost mulch in the winter (or some leaves/hay/straw, depending what I have available).

I'll do a thread with a bit more info on my growing area at some point. It is still very new and under construction but we are starting to get a good yield from it now. It's been a lot of work but very rewarding.

I read that strawberries were good companion plants for asparagus and I planted them in between my asparagus the first year. Before I knew it, my asparagus was 6 feet tall, super thick and heaving over the edges of the bed so much it needed staking. (This year, I have roped those puppies in so I can at least walk around the bed to some degree.) Needless to say, I don't think my poor little strawberries will ever bear fruit because they get virtually no sun during the growing season. If you want to plant something in between the rows, I'd go for a short season crop that wouldn't mind a bit of shade in the heat and will mature soon, like lettuces.

That's interesting too! I wonder if wild strawberries would fare better - they seem to fruit well for me, even when used as ground cover and heavily shaded. The fruits are tiny but very flavoursome. I do have my heart set on a big patch of large, cultivated strawberries one day soon.

Lettuce sounds like a good option (although, personally, I'm growing lots of it elsewhere). I'm leaning towards sticking with a perennial (or self-setting) nitrogen fixer, and probably some nasturtiums too.

Thanks

We plant asparagus amongst our black currant and red currant bushes. They like the dappled shade in the heat of summer that the asparagus gives, while still getting full sun in the spring.

The chickens cleaned out my strawberries last year so I'm trying Johnny jump ups.

I think winecap mushrooms would be a really good choice here!  The asparagus would act as shade for the mushrooms.

At a veg farm I recently worked on we developed a strategy based on research of sowing soy beans pretty heavily right after last harvest. This was mostly for summer weed control which worked quite well, while in theory building soil nitrogen. We never intended to harvest them treating it at a weed smothering cover crop although I don’t see why you couldn’t plant a nice edamame variety. We let it all die back in the fall and cut and burn fronds for asparagus beetle control. In the spring we noticed less weed pressure during harvest season over successive years.

I plant strawberries and asparagus together. Theoretically, it was supposed to be strawberries on the edges, asparagus in the middle, but in practice they're together. We get two strawberry crops per year- one in our winter (mediterranean climate, no frost), and one in summer. in winter, there are no asparagus above ground. In summer, we're grateful for the shade protection they provide. I'm not sure if it's perfect, but it's a way of having an increasing perennial edge to my vegetable garden, which is gradually moving and expanding through the circular beds. So while the asparagus is permanent, I think the strawberries will gradually move on to other beds when pest pressure is too much. Disadvantage is that asparagus likes some heavy feeding in winter, which creates conditions for things that eat strawberries. But things do generally balance out so we still get plenty of strawberries- just not saleable quality ones.

My best asparagus plants are coming up in my raspberry bed.   I had asparagus seed get into my potting soil a few years back so it's popped up in a few surprising places.  That patch is doing REALLY well.    

An update on this.

My asparagus bed has formed two different groundcovers, quite by accident. The shadier half has moss spreading all over the soil. The sunnier half has clover. I left both as I felt the nitrogen would be beneficial and, whilst I didn't expect much nutrition from the moss, it is obviously better than bare soil.

This year, when the spears began to show, the side with moss groundcover fared much better against slug attack. The slugs clearly liked the shade and moisture of the clover and would wreak havoc on the spears there. I pulled back the clover from the asparagus spears and they have coped better since.

Next year I plan to mow back the clover well in advance of the asparagus spears growing.

Heather Staas wrote:My best asparagus plants are coming up in my raspberry bed.   I had asparagus seed get into my potting soil a few years back so it's popped up in a few surprising places.  That patch is doing REALLY well.    

How is this going for you? I really like the idea of multiple perennials with the asaparagus.

We bought this place with an older asparagus patch that is completely wrapped in rhizome grass. It still produces but probably not to it's potential. My plan was to extend my raspberries and move the asparagus over there this fall and abandon the old bed until I get it under control. Not sure if the asparagus ferns will impead pollinators on late summer raspberry blooms?