How to treat HEAVY weeds before building raised beds

Forgive me if this is in the wrong area. I am new here and just getting anxious to get my garden started. Please keep in mind I have NEVER done any gardening before, so go easy on me! (but tell me if I've got it all wrong).

I have a large area available behind my house for a garden but it is currently covered in knee high weeds of all different types. The worst may be the yellow flowers with usually low lying leaves that spread everywhere. Mow them down and they are full sized flowers again in 3 days.

My plan is to weed wack the area, spray roundup (?) on the essential areas at least, and wait one week at least before placing soil/mix. Bad gopher problem in my area so I figured I would use gopher wire and weed cloth in the beds. I also thought I might just cover the areas around the outside of the beds with some of the heavy black plastic they sell at the hardware store. I believe it is actually roofing material. I'm just hoping that might eventually kill off the weeds below and keep them from coming back.

I welcome any and all recommendations as I am a complete newbie and learning as I go.

Hi DS,

You certainly have a problem.  You may be putting the cart before the horse.

Make a plan of what you want to grow and how much room you need to grow your desired crops.

Consider SFG.

http://www.squarefootgradening.org

If you like the premise get the book/s.  If you only get one get the 2nd edition.  I have both.  SFG is a system of raised bed intensive gardening.  You get a very large amount of produce from a very small, easy to maintain space.  Growing vertically really increases the capacity of your garden.

An ideal system for both the novice and experienced gardener.

Consider what vegetables you want to grow.  You will need to do some home work.  You need to determine the varieties of vegetables suitable for your region.  You will also have to research optimum planting time.

Now address the weeds. 

Do not weed whack the weeds prior to using Round Up.  Round Up works on actively growing foliage.  Use the original Round Up - not the extended care.  The extended Round Up has a pre-emergent herbicide that will not allow seeds to germinate.  Not what you want in your vegetable garden.

Read and follow the label directions.  It sounds like you have a major weed problem.  You may need more than one application.

If you have checked out SFG then you know that the boxes are lined with commercial grade, woven landscaping cloth.  Plastic is not a good solution.  It is non porous and will cause drainage problems.

SFG uses a soil less planting mix - 1/3 compost, 1/3 Peat, 1/3 horticultural Vermiculite.  If the boxes are lined with a commercial cloth and the 3-3-3 mix is used your garden will be weed free.

Good luck

I don't think good old vitamin R is quite what it used to be, be patient, it will kill the weeds, but it may take a few days. One thing I have found is that once the weeds start to go brown, they are all but dead. You can whack 'em then. But, if you cut them short with a lawn mower, you can cover them with something more easily.

DS,  Welcome to the Forum from Fresno!     You are in the Northern California Region.  I lived in Vallejo for 2 years and my daughter lived in Petaluma for several years.  You are so close to Santa Rosa where the annual National Heirloom Exposition is held at the Sonoma County Fairgrounds.  Sept 8-10, 2015, so mark the date.  There is a place in Petaluma that carries some decent compost.  You have organic dairies and other farm animals for composted manures.  Whole Food for veggie based compost or Home Depot Ecoscraps veggie compost.  If you make your own compost, washed up seaweed from the coast.

You did not state whether you will be using the All New Square Foot Gardening method.  It is perfect for weedy areas.  I recommend that you get hold of the book, 1st or 2nd edition.  It is a really, really great way to garden.  How large is the area for your garden?  There are some beautiful pictures of SFG box gardens up in the Gallery section.  One person covered the whole area with industrial grade weed cloth, set the boxes down and filled the isles with wood chips.  Looked great.  Yolos uses wood chips in her giant SFG area.

If you think that the weeds would eventually poke up through the weed fabric, you can elevate the boxes on 2' x 4's.  This also solves the problem of invasive roots from nearby trees and shrubs.

Fred has a good point about mowing the weeds short to make it easier to lay down materials.  Heavy weed fabric all over the area, gopher wire squares where the boxes will be, regular weed fabric on top of the wire, then boxes.  Fill the isles with wood chips and you will have a year around garden you can walk around, even in the rain.  Okay, okay, I'm projecting my perfect garden on you.  But, I am very excited for you.  

DITTO Sanderson on the idea of setting boxes on 2" x 4"'s You will need a plywood bottom with lots of drainage holes drilled in.

I think you would have a good result killing the weeds with RU.  Then use your weed eater to remove the bulk of the weed tops.  Use commercial quality, woven weed cloth.  The stuff you get at a big box store that looks like felt is junk. 

Build your 4' x 4' boxes and fill with Mel's Mix. 1/3 compost, 1/3 Peat, 1/3 horticultural vermiculite.

Very easy to work.  Intensive planting and vertical planting guaranties lots of produce in a small space. 

As a Newby to SFG stick to Mel's guidelines.  Don't try to get creative.  Crawl before you walk and walk before you run. 

Good luck

Wow, thank you for the recommendations and support.

I only suggested the plastic for the areas not being planted over. I just thought it would help with killing off the weeds but I can see how rain could still cause a problem with draining off the plastic, possibly into the garden areas. Certainly considering SFG method, I'm just trying to keep expenses at a minimum for the time being so keeping things on the ground would be great and make things a bit easier on me. Was planning to build by boxes using untreated cedar fence boards from Home Depot. Not the most heavy duty, but the cheapest I have found for untreated lumber.

Would it be worth it to lay down cardboard in addition to the weed cloth in the raised bed areas? I know it breaks down eventually but I have heard the weight of the bed fill on the cardboard helps smother the weeds. Again, complete newbie..

Also just had the idea to take a picture of the area I have to use, its actually quite large, but I figure pics of the weeds may help. Thanks everybody! Getting very excited.

DS,  Yes, photos will be great.  They may help us help you.  Other Newbies have posted from start to finish.  It is really satisfying seeing the transformation.

"I'm just trying to keep expenses at a minimum for the time"

- Certainly understand.  There are 2 ways to look at it.  Money up front to do something the more permanent and quality way, or bare minimum to get going knowing one may have to change things down the road.  Free wood is always the best.  I picked up scrap 2" x 4" stud lumber at a new housing development.  Yes, we had to knock out a few nails and then cut to size, but free is so nice.  We always asked the site supervisor first, then scrounged the toss pile.  I have both thick walled beds of 2' x 4's and cedar fencing planks.  The planks allow the Mel's Mix to dry out too fast in my hot summers.  However, they may work fine for Novato with the 35" of rain per year.

"Would it be worth it to lay down cardboard in addition to the weed cloth in the raised bed areas?"

-My best guess is, yes.  Also under the beds.  Plus, if you put wood chips down for the isles, it will help prevent the chips from poking holes in the fabric.  I'm thinking the thick felt-like weed fabric would also be the best for same reason. Professional or Premium grade. Free corrugated boxes behind stores. Some places recycle for cash but a few here and there can really add up to a good haul. Fresno had rain yesterday (we all danced naked in the streets ) and my new layer of wood chips was great to walk on in my slippers today!

These are just my thoughts. Except, I strongly urge you to try ANSFG. It makes veggie gardening a pleasure and not a chore.

Hi DS.  Welcome from Atlanta, GA!

Having a lot of weeds myself, and a hubby who prefers to do things more FRUGALLY, here's my 2 cents:

Yes, use cardboard (and a good thick layer of newspaper if possible) under the boxes if you put them on the ground.  I sandwiched both between 2 layers of weedcloth.  Still got grass roots coming in from the sides...

If you're putting the beds against a fence, be sure to account for that.  Weeds/grass will take any advantage.  So extend out the barriers to block them.

Sanderson's correct - do it right the first time - spend the extra $ & time on the front end to save it on the back end!  Oh, if I could do things over...  there'd be a LOT of changes in our garden plan...!

DS - PLEASE - DO NOT position your boxes along a fence. 

I did that thinking that the chain link fence would be a good vehicle for vertical gardening.  It was in a way. My cucumber did great.  

2 MAJOR problems - the cucumbers grew on my neighbor's side of the fence and were difficult to harvest.  Caring for my beds from the fence side was extremely difficult. 

Leave at least 3' between you boxes - on all sides.

Visit your big box stores and get to know the Appliance Sales Specialist.  Find out when they un-box the appliances and make it your business to be there when they do.  The boxes go into a compactor so you have to be there as they are being unboxed.  GREAT, FREE cardboard.  Put it below your weed fabric liner. 

I agree with Sanderson.  Spend a few extra $ and do it right the first time.  More cost effective in the long run.

Spend some $ and buy Commercial Grade weed barrier.  A heavy, woven fabric - not felt.  Line your entire box - bottom and side with the weed barrier.  That will help with weeds creeping in from the sides.

Sanderson has a great idea - visit construction sites and gather scrap lumber.  There is nothing wrong with scabbing boards to make your boxes. 

Another suggestion is to visit your big box stores or lumber yards and look for boards that are less than perfect. Warped or split on the end.  Talk to the store manager and make a deal. 

I practically LIVE in my local Lowe's store.  In know every one in the store and they know me.  I have made a point of developing relationships with the Nursery Sales Specialist and the Lumber Department Manager.

At least once a month I show up early in the AM with pastries for my friends.

  The NS and the LMBR Dept. Mgr. call me when they have great deals. 

My DH built 2, adjacent compost bins from scrap lumber and chicken wire. 

Until last November we had plenty of live oak leaves for browns.  Unfortunately we had to have the tree removed.

Lots of grass clippings.  Fully cured, composted horse manure from my Sister's horse farm and FREE cured compost from the Parish (county) compost facility.

Look for pallets.  Free lumber and great for making a compost bin.

Think outside the box.  If you look and ask you can get great deals on material needed for SFG. 

It is WELL worth the effort and $ to do it right the first time.

Good luck

Thanks again. One reason I'm trying not to spend too much is because I'm not sure how long we will be in this house. The cost of weed cloth, gopher wire/hardware cloth, roundup is starting to get a bit daunting. I'm beginning to think I could actually save money by putting bottoms on them and floating them on 2x4's or cinder blocks. I just don't know about finding untreated wood for that purpose unless I just use more fence planks.

I set a reminder to take photos tonight and will post an update later tonight or tomorrow morning.

DS,  If I had to move, I would take everything (well, what ever fit into my new place).  

1/2" - 3/4" plywood with holes (3/4"-1") drilled is the usual material for the bottoms. Today's plywood doesn't have the formaldehyde like older plywood. Well, at least the interior plywood doesn't.

Can't wait for your photos.

The sod could be lifted before the cardboard goes down. Leave enough room around the beds for the mower to pass.

The first picture was taken using the panoramic setting on my phone so its a little misleading. The lot is really just a large rectangle. You could put a 2 bedroom house on it and still have yard space. Our landlord doesn't use it for anything and is very generous to give us the space. The left half of the photo is pretty well lit by the sun most of the day. The right half stays pretty shaded when the leaves fill in on the trees. They were bare a week ago and should be full again in another week (Also one little crab apple tree, a great fig tree and a couple different plum type fruit trees).

Hopefully the pics of the weeds will be helpful. I'm still undecided about elevated beds or beds on the ground. Is there a particular type of plywood I should look for if I choose elevated? The most economical seems to be the 4x8 sheets of oriented strand board but I have a feeling that stuff is not safe to use in a veggie garden. I suppose I could just use more fence planks and either drill holes or leave small gaps in between. I just came back from Home Depot and bought the 1.33 gallon bottle of roundup with the pump sprayer and a long overdue echo straight shaft weed-wacker. At the very least I'd like to have the garden area cleared and sprayed this weekend.

What a fantastic area!  When you mentioned weeds, being in California I pictured a nasty mess of prickly, sticky dead stuff. Not the Garden of Eden.

I'm not sure of the Round Up at this point.  You can always return it.  Have you tried pulling up the weeds that pull up and then using a knife or linoleum knife to cut the roots under the clover and other types that can't be easily pulled up.  If the soil is still moist, I would try a square yard and see what you can accomplish just doing these 2 things, and how long it takes.  What few remaining weeds would probably smother under cardboard and weed fabric, and the wood chips in the isles and the Mel's Mix over beds may just work.  I know it's labor intensive, but I am looking at the flowering weeds on the shady right side and thinking how nice it must be for butterflies and bees.  I see that spiny weed in the third photo so wear gloves.  In the winter maybe scatter wildflower seeds.  Oh, and use the weed-whacker on the right side and leave everything in place as dead plant mulch under the trees.  Oh, what I would give for that area.

PS.  Yes, you can use 2 x 4s to elevate and place planks/boards on top in lieu of plywood, leaving 1/2" - 1" gaps between the boards.  If you go this route, I would recommend one 2 x 4 per linear length to prevent too much sagging.  The planks/boards will swell with moisture and the gap will narrow.  I used exterior grade plywood with 3/4" holes drilled in the center of each square foot and one in each corner of each box.  I think someone else used marine grade.  With plywood, you can probably get away with a 2 x 4 every 1 1/2 or 2 feet.

I went ahead and weed-wacked a little over 1/3 of the area, plenty for the boxes I'd like to install. I also raked out as much of the trimmings as possible because it was just so deep in some areas I don't think the roundup would reach the live weeds. Discovered that there are lots and lots of wild onions or something like that back there. I went ahead and used the roundup anyway and boy does 1.3 gallons go fast. We'll see if it does anything. Thinking about digging out the weeds in the actual spots where the beds will go then laying downcardboard, weed cloth, maybe even some wood chips, then my mix. When the rain hits this yard, the weeds appear out of nowhere.

The good news is I'm having 10 cubic yards of wood chips delivered for free today. A local arborist company has a sign up list for free wood chip delivery and they called today. so I should have a good amount for groundcover.

ds94947 wrote:The good news is I'm having 10 cubic yards of wood chips delivered for free today. A local arborist company has a sign up list for free wood chip delivery and they called today. so I should have a good amount for groundcover.

10 cu yards is a nice score!

Welcome to the forum DS. I am by no means an expert on either gardening or killing weeds or anything for that matter, but I thought I'd offer my $0.02. 
First of all, you are in a great spot...the people on this forum are really great and really helpful. (Check this out to see just how over and above they go to help...Thanks Boffer)

Secondly, if you have not already done so, get the All New Square Foot Gardening book (ANSFG) and read it completely. Most libraries have a copy so no cost there. If you decide to do a SFG, then I would suggest buying the book. 

One thing you will find out when you read the book is just how much you can grow in one 4'x4' box in one season...which really is multiple planting seasons. Check out the gallery and the "what are you eating threads" and you will see a LOT of veggies being grown and harvested. 

Since you are new to gardening I would suggest you start small and do 1 or 2 boxes only. It is sooooo easy to get overwhelmed and throw in the towel. That happened to me, also I learned what happens when you don't water the plants and what a hornworm is and that fire ants love corn (oops rambling) But I ended up taking a multi-year hiatus from gardening but am trying again this year. 

I am going with Table Top beds this year because I am fat and lazy and don't want to be on my hands and knees. However, the costs can add up if you are buying lumber from the stores. If you can get it for free...well who doesn't like free. 
If you are trying to keep cost down, your least expensive option would be a couple of 4x4 boxes or one 4x8 box on the ground. The 3 ingredients for the Mels Mix (the official soil for SFG) can add up but if you want good soil that is super easy to plant in and will make your garden successful then it will be worth every penny.

As far as plywood goes, I am trying it in my TT (Table Top) but I know it will eventually rot and need to be replaced. It seems like 3 years is the average for having to replace it. (Here's a picture for you) The upside of using the plywood is that if you move, you theoretically could move the whole box full of MM (Mels Mix). If it is too heavy or you need to move it by the bucket full, it should be pretty easy to shovel out with the hard plywood bottom. And yes you will want to take it with you because 2 of the ingredients in the MM, the vermiculite and the peat moss, don't break down or at least take a really long time to break down.

Last thing I will say is to try to plant easy plants...like lettuce and peppers so you can have success. Plan what you will plant and Plant what you planned, but keep in mind your plans can change and you can change your plants.

One more Last thing, be sure to find out what Region you are in and find that Region on this forum (they are down towards the bottom of the home page) and read their posts and ask those folks questions. I guarantee they will help with advice and words of encouragement.

Good luck and POST PICTURES...most of us really love them

Will follow up with more pics this weekend. I ended up covering an 8'x22' area with cardboard then Weed cloth and topped that with about 4 inches of wood chips. I'm actually afraid the weeds will be too hard to control so until I go any further I'm going to stick with this area and really just use it as a "designated garden" area. I'm planning on only doing 2 3'x6' beds anyway to start and seeing if I can even get anything to grow. I'm going to elevate the beds actually. Between the gophers and the weeds, I just have a bad feeling I could finally get things growing and then have a disaster so we'll see how these boxes go and if the weeds are kept under control I'll expand and plant on the ground next (unless I decide I love the elevated beds).

ds94947 wrote:Will follow up with more pics this weekend

Great, we love pictures.

(unless I decide I love the elevated beds).

I'm thinking Love is in the air!

DS - you have been busy.

Before you plant PLEASE go on line and query County Extension Office for your county.  Search for a vegetable planting guide.  If you can not find it call or e-mail your County Agent.  Let them know what vegetables you want to grow and ask for recommendations on region specific varieties and planting dates for both seeds and starts.  If you want cucumbers - grow them vertically.  I only grow indeterminate tomatoes.  I can grow them vertically, I can plant 3/4 plants in a 1' x 4' space, they produce over a longer period of time.

Good luck.