Wednesday, February 8, 2012

What's New at the Farm? How to Choose the Correct Cover Crop

Trivia Question: Name this Cover Crop. (Answer Below)
This week I thought I'd spend some time on figuring out how to pick a cover crop or cover crops for your garden. I'm going to use my garden as an example. My garden is 75 feet wide and 150 feet long; about a quarter of an acre. It's a clay soil with poor drainage so I can't get it tilled early in the season. It was a pasture for many years after the landowner plowed it and decided it was too difficult to put into a good forage crop.  I don't think much ever grew there, at least not that I remember, other than cherry and pine trees and some goldenrod.  The soil was poor, to say the least, when I bought it.

When growing cover crops at home there are some things to consider before planting takes place.   Hopefully after you read this, you'll be better equipped to determine the best cover crop to use for your garden. There are many factors to take into consideration when choosing a cover crop:
  • Purpose : Why do I want to plant a cover crop? Is it for soil protection only? Is it to add organic matter and smother weeds? Will I have animals grazing it? Or bees and beneficials pasturing? Is it to add nitrogen and bring minerals up from deep within the soil layers? Is it to rot sod, break compaction or improve drainage?
  • Lifespan:  Annual, biennial or perennial? How long do we want the cover crop growing here? Is this a crop we want to protect the soil until next spring, or do we want to enrich the soil for an entire year or more before using it again? Should I seed a legume for nitrogen production?
  • Seeding:  How much do I need to purchase and how am I going to seed this? Is it easily broadcast or should I be looking at something uniform in seed size?  With a mix will the different seed types spread together or will the mixed seed spread differently causing strips in the garden?  Should I seed one crop and then seed another one or can I mix them and seed at the same time? What's the most effective way to cover the seed with soil? Should I use a mix, and if so, what?
  • Time span to seed: Spring, summer or fall? Will I have time to seed it so it will perform its best? Can I get on the ground early enough to get a good stand established before I get too busy with other planting projects.
  • Maintenance:  What kind of maintenance will it need and how best to do it? Will it need mowing during its growing cycle? Can I let it do its own thing and do nothing between planting and incorporation? Will it out compete weeds, or will they present a problem later in the season? Will weeds grow in the canopy  out of sight and undisturbed for the season?
  • Fertility requirements: Does this crop demand anything to insure a good stand? Like all garden crops you want to make sure you provide everything the cover crops needs to best suit the end result. You're taking a plot of land out of production for a period of time, so why not do everything to insure that time and money isn't wasted.
  • Soil type:  The type of soil you have can determine the type of cover crop seed you use. For example, if you have packed clay you'll want to use a crop that sends out deep roots to break up and aerate the soil layers. Wet, clay soil is typically later than well-drained soil to prepare in the spring, so if you have an overwintering crop think about how much growth it's going to have the following spring while you're waiting to get into the garden. Will there be so much rampant growth to make incorporation a challenge? Well-drained, early soil means you can get a crop in early while the ground is still cool; a perfect time for clovers to become established.   
  • Incorporation: How much crop residue will I have to turn under and what's the best way to do it? Can I mow it with a lawn mower (you'd be surprised what you can mow with a lawn mower), then turn it under with the equipment I have? A cover crop that adds a lot of organic matter, well, guess where the OM comes from  the plants parts that get tilled into the soil. Winter rye if not caught in time becomes a tall, rank and unruly mess and gets harder to kill and incorporate the longer it gets to grow. It can become a challenge even for us with all kinds of equipment at our disposal.
There are many, many things one should consider before buying cover crop seed. The many varieties we offer should cover the wide range of soil types, uses and ease of incorporation for most gardeners and farmers.  A simple checklist can be made to determine the best choice for a cover crop. Now, let's see.

My Garden:
  • Size: 75' X 150'
  • Square foot area:  11,250'
  • Area for crops: 2,500'              
  • Area to Cover crop:  8,750' (0.20 acres)
  • Crop Year: 2012
  • Purpose: Smother weeds and recycle nutrients, add organic matter and prevent erosion
  • Lifespan: I plan on this ground being out of crop production for 1 year, so an annual will be fine. My garden spot is clay so I can't get in early to prepare the soil.
  • Time to seed: I'd like to clean out my henhouses prior to seeding a cover crop so I'm thinking I should be done by the first of May.
  • Fertility requirements: With the manure I apply each year, I'll need a crop that will use the nutrients supplied without adding anything. 
  • Maintenance: I really don't want to have to do much after I plant it. Maybe mow it once if needed.
  • Crop decision: Based on all these questions I have decided to plant Sudangrass (answer to trivia question above).

Here's why:
Sudangrass needs warm soil temps to germinate and grow; mid-May is when to plant and I'll have the manure applied and the ground tilled by then. Sudan grass will grow in fertile ground like my garden and very little if anything including weeds will grow in the understory.  Mowing  I can bush hog it in August when I do the annual bush hogging of my fields. It will winterkill so I needn't be concerned about regrowth next spring and I can till it under when I do my once a year rototilling. Sudangrass will protect the soil during the winter with its dead stalks and leaves, and hold the soil with its root systems.  It will provide shelter for small animals and birds during the winter, and hold some snow so we'll have ample moisture next spring.

How much seed to purchase:
The suggested rate per acre is 30-40 pounds per acre. So let's say at 40 pounds per acre, and my garden spot to cover is 0.20 acres, the amount of seed I need is 8 pounds.  Planting a little thicker won't hurt but it will help shade out weeds better and it looks like I'll need 10 pounds of seed.  I'll get it sooner than later to make sure I have it when I'm ready to plant.

Figuring out which cover crop to plant takes some time and thought, but with minimal investment it will pay dividends by breaking disease cycles, adding organic matter and recycling nutrients.  I could go on and on about cover crops but I've rambled enough for today.

As always, any questions leave a comment below and I'll try to answer it and if I can't, I'll get you an answer.

Until next week, Brian


farmland investments said...

Very interesting. Had not ever thought about a cover crop before. We have a home in a rural area with a very large garden my wife tends obsessively. I am going to pass this info onto here, although of course it may mean more work for me!

Loretta Elmore said...

Hello, I really enjoy reading your post. We are new to row cropping, we used plastic mulch last year for the first time, You would have laughed if you would have seen us trying to figure out how to use the plastic layer, but after many trials we figured it out. I love that the plastic keeps the weeds out and keeps the moisture in and the soil loose, but there are still those weeds to contend with between the rows? They got way out of hand last year, and I don't want that to happen this year. Is there anything we can plant between the rows to help keep the weeds out. Plastic is hard to pull up with weeds around it, I didn't think we would ever get it up. We have to much to keep it tilled witha walk behind tiller, and would still have to deal with the weeds next to the plastic. We don't have a pto tiller So I have about come to the conclusion to use weed spray between the rows, I really don't want to have to do that so I was wondering about planting something between the rows tho help keep the weeds down. We planted about 3000 tomato plants last year, they grew and bloomed so pretty, but the nights were so hot here,the blooms wouldn't set, so we got very few tomatoes,was a little discouraging, but what are the chances of that happening again this year? Lol, We could'nt have planted all of them without our hatfield transplanter that we bought from Johnny's, We love it and tell everyone about it. Well thankyou for all of your post, I look forward to reading more. And I will appreciate any suggestions you have. Thanks Loretta Elmore

The Harried Homemaker said...

I would like to try cover cropping, but I'm unsure how to go about it. We use the Square Foot Garden method, so tilling in crop residues isn't going to work in our raised beds. I hate seeing all that bare dirt over the winter and I know I'm missing a chance to improve the soil. Any suggestions?

Anonymous said...

Sudan grass offers challenges:

if it gets cold it is high in prussic acid
if it droughts it is high in prussic acid
until it is 24" tall it is high in prussic acid, this includes post machine harvest or animal harvest

Prussic acid is toxic to grazing animals.

If you have grazing animals you must be very careful with this grass. With that said it is an excellent summer resource.

David said...

Loretta, you might consider mulching between your tomato rows with high quality straw or first-cut hay. The thick layer of mulch will conserve soil moisture and prevent weed seed germination. Another popular method is the use of clover as a living mulch. We offer New Zealand White Clover, which is suitable for such a use. Clover will usually perennialize in warmer climates, so take care to thoroughly incorporate the plant matter after a good mowing to be sure it doesn't become a problem later on.

gayle said...

Could you give me some suggestions? Im in zone8b/heat9-south carolina, sandy soil.
For instance what would you suggest for preparing new ground?
What about a quick cover in the spring that I could plant on later?
Any suggestions would be appreciated.
I have already bought mommoth red clover, and will be getting millet in april.