My New Project — The Plants We Eat

By Jeff Gillman

The logo!

I love stories, and my favorite stories, as you might guess, are true stories about plants. One of the things that I’m best known for here at the UNC Charlotte Botanical Gardens is telling random stories about some odd tidbit or another to students trapped in my classes or visitors locked into garden tours, but recently I found a new way to share my collection of those eclectic plant stories: Podcasting. Not only do I get to talk about all the things that I love to talk about, only those people who really want to hear about them have to listen. It’s a win-win!

Recording the podcast!

From apples and artichokes to digitalis and peyote, our world is full of amazing plants that we interact with on a daily basis. This greenery can sustain us, intoxicate us, cure us of disease, and even kill us.

I have had the opportunity to read about and work with an incredible variety of plants, but the ones that I find most fascinating are those we ingest as food or medicine, and that’s what this podcast is about. From toxic honey made from Rhododendrons to the incredible photosynthetic efficiency of sugar cane and the natural genetic modification of sweet potatoes there are an incredible number of stories that the plants around us have to tell, but if you’re just interested in growing these plants then we have you covered there too. I am doing these podcasts with a friend of mine, Cindy Proctor, who loves to talk about how to grow these plants, so there’s plenty of that in the podcast as well.

Rhododendron from which Mad Honey is made

So to make a long story short, we would love it if you would take the time to listen to our podcast. You can find it on the podcast app on your iPhone or on Sound Cloud, or here at the Botanical Gardens website.

And since we’re new at this we would love it if you would let us know what you think. You can comment on the blog post here, or on the post on Facebook, or feel free to write to me at jgillman@uncc.edu.

It’s all about location, location, location

Whenever we (the Garden Professors and our community) answer garden questions, we almost always will ask the location of the garden.  I’m sure this frustrates some people who think that plants act the same wherever they are.  However, this is not the case.  There isn’t a one-size-fits-all to most garden questions.

For example, I work on the east side of Nebraska in Omaha, along the Missouri river.  The environment (weather, soil, etc) here is vastly different than where I’ve spent most of my life in West Virginia.  I had to re-learn how to answer questions when I moved.  The soil pH is different (I’m still lamenting the fact that I can’t grow blueberries in Nebraska), the precipitation is much lower.  Even now when I appear on the statewide gardening show Backyard Farmer, I have to keep in mind the location of the incoming question.  The western side of the state is even drier than the eastern side, the growing season much shorter, and recommendations are vastly different.

The difference of where plants can grow and can’t is even more apparent when you travel to vastly different climates.  I recently came back from a trip to the tropical paradise of Costa Rica.  Many of my traveling partners and friends back home were blown away with the abundance of plants growing in yards, farms, and even in the wild that cannot grow “back home.”

The most common bedding plant in lawns were a popular holiday favorite here in the states – amaryllis.  They were planted in abundance along sidewalks and driveways.

Amaryllis prolific in a Costa Rican yard

I visited a diversified coffee farm that was using Dracena (a common houseplant) as living fence posts in their vegetable garden. (And did I say coffee farm – nothing like drinking a farm fresh cup of coffee right on the farm).

Living Dracena fence posts at a Costa Rican coffee and vegetable farm

Tillandsia air plants were growing like weeds (which is basically what they are) on the trunks of trees.

These are all tropical plants that won’t survive in colder or drier climates of the US.  (The southern US states can grow more tropical stuff, but is is a small portion of the country.)

Many of the plants we grow both indoors and out here in the states come from different areas and grow differently in those areas than they do here.  Our vegetables come from all over the world.  So do our flowers and houseplants.

Plants from warmer areas either have to be grown indoors or as annuals even if they are perennial or evergreen in their native environments.

This is why the location of your garden, environment, and even the microclimate in your yard is important to know when selecting plants.  Aside from the difference of what can grow, plants grow much differently in Florida than they do in Minnesota or Virginia. And why it is important information when you’re asking questions about how to grow plants or control insects and diseases – because its all about location, location, location.

Bonus: Cashew apples!

 

Master Gardeners at a crossroads

{Warning. Today’s post is a rant. So I’ve illustrated it with pretty flowers in soothing colors to make it more palatable.)

Hydrangea

Anyone who gardens in the United States will be familiar with Master Gardeners. The Master Gardener program was started by Washington State University in 1971, when Extension agents in the largest urban counties found themselves overwhelmed with questions from the gardening public. These agents proposed training volunteers to help with educational outreach efforts, and with support from the university the first Master Gardener program was born. The history and function of Master Gardeners is further detailed in a couple of articles I co-authored (Chalker-Scott and Collman 2006 and Chalker-Scott and Tinnemore 2009): the more recent article also raises concerns about the decline of programmatic support in Washington state and elsewhere. If you’re a Master Gardener, the repercussions of this should alarm you.

Iris

What makes a successful Master Gardener? According to Sharon Collman, the last surviving founding agent of the WSU program, it begins with this:

  • A commitment to basic and advanced training program;
  • An open-minded approach to continuing education of themselves as well as others;
  • A willingness to provide science-based, unbiased information regardless of personal beliefs. (From Chalker-Scott and Collman, 2006)
    Pink fawn lily

    To be successful, volunteers need high-quality education consistently provided by university discipline experts. And that’s where the model is starting to fail in Washington state. Extension specialists who used to provide training to Master Gardeners in plant pathology, entomology, lawn and turf management, soil sciences, and other important fields have not been replaced by the university when they resign or retire.  More and more training is left to the devices of individual counties, whose Extension funding from WSU has been gutted over the decades. The previous university-centric approach to Master Gardener training has devolved into volunteer-driven county programs with little educational oversight.

Morning glory

While counties should be commended for keeping programming alive in the face of crippling budget cuts, the lack of meaningful curricular oversight by the university means that volunteers often don’t get the most current and relevant information pertaining to the science of gardening. Worse, they may be taken in by popular products and practices with no basis in science. Other volunteers may let their personal beliefs interfere with their pledge to provide objective, science-based information on topics including pesticides, GMOs, and other controversial topics. This undermines the credibility of the county program and ultimately the university who claims these volunteers.

Oregon oxalis

If you are a Master Gardener in Washington state or anywhere else in the U.S., it’s really incumbent upon YOU to insist that your land-grant university live up to its public outreach mission. You DESERVE access to Extension faculty specialists whose primary focus is to educate the gardening public.  The university takes credit for your volunteer hours when they make reports to the state legislature. Make them earn it.

Rose

Don’t waste your time contacting the university – you’ll get nothing but platitudes there. The place for change to start is with your elected state representatives.

Arbor Day of Horrors

Happy Arbor Day!  What, you aren’t celebrating?  As a recent transplant to the state of Nebraska, I was amazed to learn that the Cornhusker State is the birthplace of the day we set aside to celebrate trees.  (Since most people associate the state with corn, football fanatics, and steak).  And since Arbor Day is near and dear to Nebraska, it is the only state that celebrates it as a civic holiday (most state offices were closed – no drivers license for you!).

The holiday got its start in 1872 when J. Sterling Morton of Nebraska City, Nebraska (just 40 miles south of Omaha) organized the planting of one million trees in the state of Nebraska on April 10.  Morton had been a newspaper editor, acting governor of the state, and after he founded Arbor Day was the 3rd US Secretary of Agriculture, having been appointed by President Grover Cleveland.

He built a mansion in Nebraska City that was later remodeled by his son Joy Morton (who had lots of money since he founded a little company called Morton Salt – maybe that’s where the anecdotal info of using salt to kill tree stumps/weeds started!).  These days the mansion is part of the Arbor Lodge State Historical Park.  The Arbor Day Farm is also part of the park, where locals and tourists alike stop for apple orchards, a tree playground, and wine tasting.

The modest Arbor Lodge, as captured when we were being tourists in our new state.

But if you haven’t planned a trip to Nebraska City for Arbor Day and you want to celebrate it at home by planting your own tree….well, there are some definite right and wrong ways to do things.  So I thought we’d invite people to share their tree horror stories.

What have you seen that just makes you go huh?  Do you have stories or pictures that are worthy of the carnage over at Crimes Against Horticulture?

Like the always frightening Mount Treesuvius?  (down with Tree Volcanoes!)

Image may contain: tree, plant, outdoor and nature
Mount Treesuvius – as captured by the Nebraska Forest Service

Or how about the girdling root stanglehold of slow death?

Image result for tree girdling roots

Or this truck-meets-tree first date fiasco that was sent in to our Extension gardening show Backyard Farmer this week?  (My diagnosis: prepare for last rights).

Photo via Backyard Farmer

Have you seen poorly planted, improperly pruned, damaged, or scary trees? Share your stories, pictures, and laments in the comments or on our Facebook page.

 

When spring is delayed

Enjoying our first day above 55 F in quite a while here in mountains of Southwest Virginia. We’ve had far-below-average temperature and three significant snow events over the past four weeks.

Saturday, April 7, 2018 at our farm (Newport, VA).  Not making me want to garden.

For much of the Mid-Atlantic, Northeast, and Midwest, spring has been very slow to arrive. The jet stream has been riding mighty low, and is taking another dive next week. For gardeners, this is frustrating (see above), though here in USDA Hardiness Zone 6b, we’re still well within the “last freeze” window.

For ornamental plant nurseries, greenhouses, and retailers/garden centers in these regions, this is darn close to devastating (the South has fared much better).  For growers and retailers, spring is the busiest time of the year – many see 70-80% of their annual sales between March and early June.  Of that amount, at least 50% of retail garden center sales will happen over the weekends.  IF it is nice.  Folks stay away in droves when the weather stinks. And this has repercussions down the supply chain.

Chris Beytes, the editor of GrowerTalks and GreenProfit (two highly subscribed-to publications within the greenhouse and garden center sector), has been keeping track of spring sales for years.

Growers and garden centers self-report a weekend rating on a scale of 1 (dreadful) to 10 (can’t keep product on the shelf, happily exhausted, planning vacation in Tahiti).  Not all states end up represented – either they’re too busy selling (Florida!) or too depressed to report (possibly Ohio!).

Here’s last week’s map (click for a link to Chris’s newsletter column)

Lots, lots of gray.

Closer to home: I took my Ornamental Plant Production and Marketing students on a field trip last Friday. We toodled up I-81 to visit a container nursery (woody plants) and a wholesale greenhouse focused on quality bedding plants and baskets for the independent garden center (IGC) market.

The greenhouse was absolutely packed to the gills with market-ready annuals, herbs, veggie transplants, and hanging baskets.

And it was eerily quiet.

A Friday afternoon in April, and the only folks in a wholesale greenhouse…were the owners. THIS IS NOT NORMAL.  There should be workers, carts, trucks, beeping, yelling, transplanters cranking, etc.

Weather over the previous weekend and early week had been spectacularly crappy. Because the garden centers across the region had not moved enough product to restock, there was no shipping. Because there was no shipping, there was no space freed up to put anything else.  Because there was no space, no transplanting could occur, and seedlings/liners were still in their trays.  Calls were probably being placed to the propagation greenhouses that grow the plugs/liners, asking them to hold off on shipping until the finishing grower could clear out the backlog of plug trays.  Plus perfect plants stay perfect only so long. Pesky things tend to grow/flop/get pests and pathogens.

I love for students to see the real-world hustle/bustle/insanity of spring that growers face each year. The act of growing plants is what sparks the interests of the students – but  understanding the supply chain and market behavior is just as important. We did get great tour – along with a  lot of fodder for class discussions.

Hopefully things will warm up; garden centers across the regions will be jam-packed, and all will be well. If this paralysis continues much longer, the window of opportunity will start closing.  It gets warm/hot, schools let out, folks go on vacation…and lose that got-to-garden feeling.

You can help repair this logjam (yes you can!). Regardless of the weather this weekend (because you’re a tough cookie/Garden Professors reader), get thee to your favorite garden center or retail greenhouse this weekend. And buy! Buy! Buyyyyy!

Let’s be rational about roots

One of my colleagues alerted me to a blog post on tree myths currently making the rounds on social media. As a myth debunker myself I was particularly intrigued by the last myth “Root Pruning Stimulates Root Branching:”

“When planting a tree’s root ball, It is very tempting to cut back on roots that are circling the ball. It is very often thought that a dense root ball will stimulate new feeder root growth…but that is not the case.

“Don’t worry about encircling roots as they will correct that on a new site.

(Yeah right)

“Most new root growth occurs at the end of existing roots. Root pruning is often done at the nursery to accommodate packaging and to resume growth before the final sale. If you are planting the tree at its final site, it may be best that you gently break up the root ball but never prune root tips.”

Most surprising of all was the statement at the end of the post which cited an Extension publication by Dr. Ed Gilman at the University of Florida.

Let’s straighten this out (pun intended).

First of all, root pruning DOES stimulate new root growth. It’s just like the response you see when you prune the crown of a plant – the buds below the cut become active and develop into new shoots. There are growing points behind the cut ends of roots which act in the same manner.

Young root branching

Second, circling roots will NOT correct themselves after planting. If they are flexible, you can tease them out to radiate from the trunk. If they are woody, you will have the same luck straightening them as you would in straightening a dowel. If anything, it’s going to break. Not bend.

Seriously. You think this root is going to straighten out?

Finally, root elongation (growth) DOES occur at the end of existing roots – IF they are intact. If they’ve been cut, then we’re back to my first point.

This is basic plant physiology. The response of roots to pruning has been known for several decades. So how could the University of Florida publication be so wrong?

Excessively long roots can easily and safely be pruned before planting

I was able to track down the publication “Dispelling Misperceptions About Trees“. It was written in 1991 and has since been archived – meaning that it’s not considered to be a current source of information any longer. But let’s take a look at what it says, especially the underlined portion:

 Root pruning does not stimulate root branching all the way back to the trunk. Roots are often pruned before moving a tree in hopes of creating a denser root ball.However most root growth after root pruning occurs at the end of the root just behind the root pruning cut, not back toward the trunk. Therefore, dig the root ball of a recently root pruned tree several inches beyond the location of the root pruning. Root pruning should be conducted 6 to 10 weeks before moving the tree. Root pruning more than 10 weeks before moving the tree will reduce the advantages of pruning, because regenerated roots will quickly grow outside of the root ball.”

Root pruning when these trees were dug results in many new flexible roots

This says exactly what I stated in my first point: root pruning stimulates new root growth – which is root branching.

Dr. Gilman’s document goes on to say:

“Roots circling around a container do not continue to grow in a circle once the tree is planted in the landscape. Roots frequently circle within the perimeter of a container several times before the tree is planted into the landscape. The portion of the root which grew in the container does not straighten out, but new growth on this root will not continue to circle.”

So yes! You DO need to worry about those circling roots!

Circling roots turned this crape myrtle into a crap myrtle (Courtesy of Roger Duvall)

In 1991 Ed was an assistant professor at UF and went on to write hundreds of Extension publications and research articles during his career. And in 1991 he was well aware of how root pruning affects root growth.

The moral to this story: read your sources carefully and cite them accurately. And if what you read doesn’t jibe with the current state of science, ask questions!

A Raised Bed Rebuttal: In defense of a common garden practice and soil health

One of the things I miss (and sometimes don’t miss) after my move from West Virginia to Nebraska is writing my weekly garden column for the Charleston Gazette-Mail newspaper.  It was a great way to always keep thinking about new things to talk about and a great way to connect with the public.

After I left, the newspaper replaced me with a team of 4-5 local gardeners who would take turns writing about their different gardening insights and experiences.  Some have been really good, like the ones who were my former Master Gardener volunteers.  However, sometimes I find the bad information and attitude of one of the writers off-putting and even angering.

Take for example this missive which equates sustainable agriculture (a term which is pretty well defined as a balance of environmental stewardship, profit, and quality of life) solely to permaculture and biodiversity while espousing an elitist attitude about “no pesticides, no fossil fuels, no factory farms, growing all you need locally and enhancing the land’s fertility while you’re at it.”  He got all this from an old photo of dirt poor farmers who were apparently practicing “permaculture” – which I’m sure was foremost on their minds while they were trying not to starve to death.  The fact is that our food system (and the food that today’s low income families) depends on comes from a mix of small and large farms. And most of those “factory farms” are actually family owned, and not everyone can afford to grow their own food or pay the premium for organic food (which still has been treated with pesticides and is in no way better or healthier than those conventionally grown).

Now, I know I no longer have a dog in that fight, but when I see bad information, especially when it is aimed toward an audience that I care deeply about I just have to correct it.  So two weeks ago when I saw his latest gem of an article berating a woman (and basically anyone) for using lumber (and those who work as big box store shills to promote them) to build raised bed gardens and should instead till up large portions of their yard for the garden I was aghast.  Putting aside the horrible advice to till up the garden (which we’ll talk about in a minute) or the outdated recommendation of double digging (proven to have no benefit), that advice is just full of elitist assumptions toward both the gardener and toward the technique. It is especially ridiculous and ill-informed to suggest that tilling up a garden and destroying the soil structure is much better ecologically speaking that using a raised bed (and we’ll talk about why in a little bit).

Don’t want to do a raised bed?  Fine, it isn’t for everyone.  But that doesn’t mean you should go out and till up a large patch of land that will degrade the soil, lead to erosion and runoff, and reduce production.  It does not do anything to improve drainage nor aeration.

So let’s do a breakdown of why I find this article, its assumptions, and bad science so distasteful:

Bad Assumptions (and you know what they say about assuming)

The gardener didn’t have a reason for a raised bed other than she had been told that’s the way you do it.

This assumption fails to take into account the many different reasons why a gardener may prefer to use a raised bed.  Does she or a family member have mobility limitations where a raised bed would provide access to be able to garden?  Or does she have space limitations for a large garden patch?  Would a raised bed make it easier for her to manage and maintain the garden?  Making a blanket pronouncement against the technique fails to use empathy to see if it actually would make gardening more accessible or successful for the gardener. Is she wanting a raised bed because the soil in the ground at her house is too poor or contaminated?  West Virginia is notorious for having heavy clay, rocky soil that is pretty poor for growing most crops.  It can take years of amending to get it even halfway acceptable for gardening.  Or perhaps she lives on a lot that had some sort of soil contamination in the past and she’s using raised beds to avoid contact with the contaminated soil.

Raised beds also have some production advantages – the soil heats up faster in the spring, allowing for earlier planting.  A well-built soil also allows for improved drainage in areas with heavy soil or excess moisture.

The gardener has access to equipment to till up a garden space, have the physical strength and endurance to hand dig it, or is she able to afford to pay someone to do it for her?

Raised beds can often be easier for gardeners to build and maintain, often not needing special equipment or heavy labor.  If the gardener isn’t supposed to benefit from these efficiencies, how will she go about tilling up the soil for her new garden.  Does she or a friend/neighbor have a rototiller or tractor she can use?  Is she physically capable of the often back-breaking work of turning the soil by hand?  Or does she have money to pay someone to do it for her?  So these “cheaper and easier” methods he describes could actually end up costing more and being harder than building a raised bed.

The raised bed has to be built out of lumber, which apparently only comes from the Pacific Northwest and is a horrible thing to buy. First off, raised beds can be built out of a number of materials.  The list usually starts with lumber.  Some people tell you to use cedar (which does primarily come from the PNW), since it is more resistant to decay, but plain pine that’s treated with a protective oil or even pressure treated is fine (it used to be not OK back before the turn of the century when it was treated with arsenic, but most experts now say it is OK since it is treated with copper).  The dig against the PNW lumber industry is as confusing as it is insulting, since there’s lots of lumber produced on the east coast, and even a thriving timber industry right in West Virginia.  Most lumber these days is harvested from tree farms specifically planted for the purpose or by selective timbering that helps manage forest land for tree health and sustainability.

The list can go on to include landscaping stone, concrete blocks, found materials like tree branches, and on and on.  These days, you can even buy simple kits you can put together without tools and with minimal effort that are made of high-grade plastic or composite lumber.  They’re getting cheaper every year, and can be especially affordable if you find a good sale or coupon.

Heck, a raised bed doesn’t even require the use of a frame at all….just a mound of well amended soil in a bed shape will do.  No need to disturb the soil underneath, just get some good topsoil/garden soil in bulk or bags from your favorite garden center, mix it with a little good compost, and layer at least 6 inches on top of the soil.  Use a heavy mulch on top if you are afraid of weeds coming up through the new soil.

The soil she’d buy is trucked in from Canada.

I’m guessing this has some sort of assumption that the soil a gardener should be putting a raised bed is like a potting mix composed primarily of peat moss. While many gardeners are trying to decrease the use of peat moss, which is a non-renewable resource harvested from Canadian peat bogs, the recommended soil for a raised bed is not potting mix or one that even contains a large amount of organic material.  The recommended composition of raised bed soil is largely good quality top soil, which is usually sourced locally, mixed with a bit of compost which could be from home compost, a local municipal composting facility or producer, or from a bagged commercial product that is likely from a company that diverts municipal, agricultural, and food wastes into their product.

Bad Advice based on Bad Science (or lack thereof)

Tilling or disturbing the soil is a common and acceptable way to prepare a garden.

More and more evidence is emerging that tilling or disturbing the soil is actually one of the worst things you can do in terms of both production and environmental impact in agricultural production.  First, tilling disturbs and in some cases destroys the soil structure.  Destroying the soil structure allows for increased erosion, especially when the bare soil is washed away during heavy rains or blown away in heavy winds.  Excess tillage and wind is what actually led to the dust bowl, which actually led to the early promotion of conservation tillage practices through government programs like Conservation Districts (and also gave us some great literature, thanks to John Steinbeck).  Aside from the soil particles that erode, having open, tilled soil leads to nutrient runoff that contribute to water pollution.

 One other structure negative is the production of a hardpan or compressed layer of soil that occurs just below the tilled area.  This results from the tines of a tiller or cultivator pressing down on the soil at the bottom of where it tills and can drastically reduce the permeation of water and gasses through the soil.

Alt
Soil Aggregates and microbes

The aggregates in the structure of un-disturbed soil provide myriad benefits to soil health, especially in providing the capacity for the growth of good microorganisms.  Studies have shown that the population of soil microbes is drastically higher in agricultural soils that haven’t been tilled.  Therefore, tillage reduces soil biodiversity.

One of the reasons for increased soils microbes in no-till soil is an increase in soil organic matter.  No-till allows for some crop (roots, etc) to remain in the ground and break down.  Tillage also incorporates more air into the soil, which does the same thing that turning a compost pile does – it allows the decomposition microbes to work faster in breaking down organic matter.  This increased activity then decreases the amount of organic matter.  So tilling the soil actually reduces organic matter.  The structure and organic matter also allows no-till soil to have a higher Cation Exchange Capacity, or ability to hold nutrients.

When the carbon in the organic matter in the soil is rapidly depleted after tillage, it doesn’t just disappear.  The product of the respiration from all those bacteria and fungi is the same as it is for all living creatures – carbon dioxide.  The organic matter held in the soil therefore provides a great service (we call this an ecosystem service) in that it sequesters carbon from the environment.  This can help mitigate climate change   and even effect global food security.

Source

Double digging does a garden good.

Look through many-a garden book and it will tell you to start a garden bed by double digging, which is a term used to describe a back breaking procedure where you remove the top layer of soil, then disturb a layer beneath it and mix up the layers.  While it may not be as drastic as running a tiller or tractor through the soil, it still destroys the structure with the same negative outcomes as above.  Additionally, while many gardeners swear by it, there is evidence that the only benefit to come from it is to prove to yourself and others that you can do hard work.   It has no benefit for the garden and usually negative effects on the soul, psyche, and back of the gardener.

Large tilled up gardens are easier to maintain. One of the benefits of gardening in a bed, raised or otherwise, is that the close spacing allows you to grow more stuff in a smaller area. By reducing the area under production, you also reduce the labor and the inputs (compost, fertilizer, etc) that are used.  Using the old in-ground tilled up garden method where you grow in rows means that you have more open space to maintain and will be using inputs on a larger area that really won’t result in more production (it is really wasted space and inputs).

So, how do you start a garden if you don’t want to build a raised bed and know that you shouldn’t disturb the soil?

So you realize that tilling up the soil is really bad from both an ecological and production standpoint, but you don’t want to build a raised bed structure? That’s perfectly fine.  Gardening in a bed, raised or not, is a great, low-impact gardening practice.

To get started, you don’t have to disturb the soil at all.  Simply adding a thick layer of compost and topsoil on top of the soil in the general dimensions of the bed is a good way to start a bed.  No need to till or disturb.  And over time, the organic matter will eventually work its way down into the soil. If you have really heavy (clay) soil, you’ll probably want to start with a fairly deep (at least 6 to 8 inches) layer of soil/compost.

Just cover with your favorite mulch to keep it in place and reduce weeds (I prefer straw and shredded newspaper, but you can use woodchips as long as you don’t let them mix in with the soil – something I never can do in a vegetable garden where I’m planting and removing things on a regular basis). Keep in mind that a good width for a vegetable bed is about four feet and you want a walkway of at least two feet between them.  This allows you to not walk on the good soil, which can cause compaction.

If the spot where you want to put your bed is weedy, use your favorite method to remove weeds before laying down the layer of compost/soil.  This could be through herbicide usage (keeping in mind most have a waiting period to plant, though some are very short) or mulch.  If you are planning ahead (say at least a year), our Garden Professors head horticulturalist suggests a layer of woodchip mulch 8-12 inches deep that can turn a lawn patch into a garden patch.  They reduce the weeds and build the soil as the break down.