Keep Critters Out of Your Raised Beds with an Animal Barrier

Welcome to the last in our series on raised bed gardening. As you probably know by now, we received so many responses from my email group that this raised bed podcast turned into a three-part series. If you would like to join the conversation and contribute to future topics, I invite you to click the red “Get Free Updates” button at the top of this page.

In Parts One and Two of this series, we covered everything from finding the perfect location for your raised bed garden to material choices, the perfect soil “recipe” for your beds and lots more. So if you haven’t listened to those podcasts, I recommend you start there to get you up-to-speed for all that will be covered here.

Now that we’ve covered the basics in planning, construction, and maintenance; let’s dive into some common and specific questions asked by my email group.

Using Cover Crops – Green Manure

Some gardeners rely on – and some resources recommend – planting cover crops.

The intended benefits of a cover crop are twofold: Protect (mulch) the soil surface, and add nutrients and organic matter to the soil subsurface. The benefits of cover cropping are undisputed, and a standard practice in organic agriculture. In fact, it’s an essential practice to achieving ultimate soil health in those applications where it’s practical.

Yet if you’ve been following along, you probably already know that I prefer to use a layer of organic mulch over my raised garden beds. I also prefer to add organic material and nutrients by using one or a combination of those organic ingredients I keep mentioning from Part Two of this series. My rationale has a lot to do with practicality in managing raised bed garden soil.

Why? As I explain in Part Two (there is so much information there!), I follow a no-till method of gardening. A short soliloquy on why I don’t till: It breaks up much of what I am striving for when building my healthy soil ecosystem.

Cover crops are typically cut down, and often, the crop and the soil bed are tilled together. For me, the drawbacks of this approach outweigh the benefits in a raised bed home garden.

What is a cover crop? Green manure aka cover crops can be any one of some materials – like rye, field peas, buckwheat, clover, etc. – planted between growing seasons. Many cover crops develop strong, deep root systems.

Ideally, the roots of the cover crop are allowed to break down (rot) over time, adding organic matter to the bed. Until they break down, they are taking up valuable root space in the garden bed. Some popular cover crops are heavy grasses, and their root systems can be tough to get out when preparing for your edible crops.

I find that using cover crops is more work than the benefit I attain in a home garden raised bed, and I achieve the same benefits of cover cropping (with less effort) by top dressing with compost or other organic amendment and always using an inch or two of mulch.

Whichever route you choose – never leave your soilbed exposed.

It was covered last time, but it cannot be to oft repeated… mulch is a magic bullet in your garden. When you keep your raised beds covered with an inch or two of organic mulch – like leaves or wood chips – you will simultaneously:

• Reduce weeds – Seeds blowing in can’t take root, and seeds in the soil can’t germinate without the sunlight hitting the soil surface.
• Moderate the soil temperature – In extreme heat or cold, mulch will act as a barrier to your soil temperature and those plant roots.
• Reduces evaporation – Wind and heat from the sun don’t have a chance to dry out your soil when mulch is in place.
• Blocks disease – Even in healthy soil, there are diseases lurking down there. During a heavy rain or splashing irrigation, those diseases can splash up from the dirt onto the foliage of your plants unless…. Ah yes, you have mulch preventing any water from splattering up in the first place.

Oh, how I love my mulch.

Some of my email group noted the common use of black plastic row cover instead of mulch. This is a popular option for in-ground rows, and an application example is strawberry growth in large commercial operations.

Black plastic can reduce evaporation, but it can also really bake the covered soil. For that reason alone, I’m not a proponent of black plastic. Plus, well, it’s plastic. Again, I also prefer that mulch breaks down over time, further feeding my soil. In my experience, black plastic just can’t compete with a good layer of mulch.

Do I use mulch on my pathways? Sure do. I use 2” of mulch on the spaces between my GardenFarm raised beds. It does a remarkable job keeping weeds at bay, and it looks nice too.

I, typically, have to spend time weeding just once each season, and I prefer to use a scuffle hoe for that job. The scuffle hoe cuts the weeds at the surface – making quick, effective work of it.

You might also choose to use a layer(s) of cardboard or other organic material to mulch between your raised beds – any of which are great options. If you have hardscaping between your beds, a scuffle hoe won’t fit the bill for you, so you may want to use a flame weeder or resort to hand pulling.

An organic herbicide is another weed management option, but I’m always leary of the unintended harmful effects that organic herbicide – like vinegar – can have on amphibians and other beneficials that I strive to keep around in my garden.

Can oak leaves be used as mulch? Indeed. Yes, oak leaves are highly acidic (around 4.7). When used as mulch, they remain on the soil surface, so there will be a buffer from much impact to your soil pH. As they break down and join your soil, their pH level will neutralize.

Oak leaves are slower to break down than many other leaves. Some will see this as a drawback, others as a benefit. As for me, I prefer materials that break down fairly quickly.

One way to encourage their breakdown – should that be your preference – is to shred them. The smaller shreds break down much more quickly than whole leaves, and – bonus – they are also easier to apply to the soilbed.

You might also consider adding oak leaves to your compost pile. If so, I definitely recommend shredding them first. If you have lots of oak leaves, it would be worthwhile to designate a compost bin just for oak leaves. Keep them moist, mix them up periodically, and allow them to break down to a more benign material.

How do I shred leaves? There are many ways to doing this. Use a chipper shredder, or you can mow over the leaves and pick them up with the bagger.

A more creative approach is to place the leaves in a large plastic bin (picture a garbage can) and lower your string trimmer down into the bin. That string will shred the leaves pretty effectively (like an immersion blender), and I must admit, it’s a little fun to watch.

What Should you Plant in your Raised Bed Garden?

When choosing what to plant, consider your space. You can grow nearly anything in your garden beds. It’s the raised bed “real estate” available in your garden that is, by and large, your only limiting factor.

If your beds are around the minimum depth of 6” or so, you can still grow root crops, but you will be stretching the limits a bit. As mentioned in Part One of this series – if you want to grow potatoes, carrots, parsnips, etc.; consider starting with deeper beds (up to 18”).

Perhaps you have a huge raised bed garden area? You might well be happy to designate some of that space to a more permanent crop – like asparagus. Asparagus crops improve when they re-sprout year after year in the same location. Berry bushes could also be grown in a raised bed situation – again, should you choose to allocate space for them to remain indefinitely.

If you want to keep your gardening options open, you may want to stick with those one-year crops; like tomatoes, eggplant, corn, potatoes, cantaloupe, watermelon, etc. Yep – I did include cantaloupe and watermelon in that list. I’ve grown them in the GardenFarm raised beds, allowing their vines to trail down into my walking paths. I was happy to give them that space in return for their sweet produce.

Some plants, I prefer to grow in-ground simply because I don’t want to surrender raised bed space. An example of that is my blueberries. My blueberry bushes grow happily – and indefinitely – in the ground just outside my raised bed gardens.

It’s largely all about how you choose to use your space. Don’t hesitate to mix your crops or grow them in neat rows or squares. Simply make the best use of the space you have to work with.

Speaking of Space – Care to Know How to Space those Plants?

How close should those rows or squares be? How tightly can you mix those crops? There is no hard-and-fast answer to those questions.

When I’m planting my raised beds, I do so with an understanding of how large I expect each type of plant to get, and I space them so – at fully-mature size – they will be barely touching each other. I do that to allow good air flow and light to reach each plant and all the areas of the plant.

Restricting airflow and light is a great way to encourage pests and disease into your garden beds. Plants can also shade each other out when they are too close, and you don’t want that to happen.

As an example, I plant four tomatoes in one of my 12’x4’ raised beds at the GardenFarm. In those instances where the plant is indeterminate, size can be controlled by the cage or other support structure you have in place for the plant. I like to give my tomatoes plenty of room to spread out and produce copious crops.

If in your gardening experience you have done battle with pests or disease, try opening up the spacing a bit this season. The impact of spacing on pests and disease does depend somewhat on the type of plants you are growing, your environment, and – again – the health of your soil. So, don’t be afraid to experiment with spacing – just remember that providing that air flow and light really is important.

For those of you who are interested in mixing your crops, let’s dive into companion planting. This was another popular topic for questions.

The Fact is – There Aren’t Many Facts on Companion Planting

There is some physical, chemical and biologic evidence; but there really isn’t much in the way of valuable, measurable scientific evidence on companion planting. In fact, companion planting was covered in one of my Myth-Busting series with Linda Chalker-Scott.

A common companion planting example is The Three Sisters. The corn, beans, and squash of The Three Sisters combination don’t rob each other of nutrients in the soil, and they do benefit each other.

The beans are a nitrogen fixer – adding nitrogen to the soil for the corn and squash (or any other plants surrounding the beans you plant). The corn provides physical support for the beans to climb. The large leaves of the squash effectively mulch the surface where The Three Sisters are growing, shading out the sun and protecting the soil and plant roots.

In other words, The Three Sisters provide some basic, fundamental benefits to each other – but they aren’t unique to that specific grouping. Corn, for example, could also provide structure to snap peas or any other climbing edible.

If you do mix your crops, don’t feel the need to customize your soil amendment to pamper certain crops. Most everything you grow will thrive with the same, neutral pH level and access to the same nutrients. There are a very few exceptions, like blueberries which want that acidity. For those exceptions, plant in a separate bed or in-ground.

RAISED BED WITH HINGED CRITTER CAGE to deter deer, rabbits and critters from the garden.

FAQ

How to protect a raised garden bed from animals?

Netting or Wire Mesh: Use bird netting or wire mesh to cover individual plants or garden beds. Ensure it’s secured at the base to keep animals from getting underneath. Cages: Build cages for vulnerable plants using chicken wire or hardware cloth. This is particularly effective for seedlings and young plants.

How do I keep pets out of my raised garden bed?

Opt for a location for your raised garden beds that is less accessible to your pets. Consider placing them away from common pet pathways or areas where your pets like to play. Create a visual and physical barrier by installing an attractive border fence around your garden beds.

How do I keep rodents out of my raised garden bed?

Put hardware cloth under your beds at the time of installation to keep the pests from coming from below and digging into your beds from the bottom. Hardware cloth is metal sheeting that looks like mesh. You can find rolls of hardware cloth in the fencing section of most big box stores.

How do I protect my raised garden bed from squirrels?

Netting, fencing, or even burlap covers can provide shelter and protection for smaller spaces and raised garden beds. Kinley makes her own cone-shaped cages to protect coral bells and other perennials until the plants are thriving in the spring and uses chicken wire to protect bulbs as they begin to sprout.