Tomatoes are the crop that started me into gardening. Now I grow several hundred plants every year.
The best raised bed for tomatoes is natural wood, 2 feet tall, and a maximum 4 feet wide. The soil should be filled with 15-20 percent compost, and have good drainage. It needs to have 3 square feet per large plant, be should be strictly no-till, and not have a barrier underneath it.
There are a few variable factors here and a lot more to discuss. Plant variety, soil fertility, weather, and number of plants all matter. But, there are some things that apply across the board.
3 Points to the Perfect Tomato Bed
Tomatoes are heavy feeders. They need a lot of nutrients to keep up growth, continue to put out blossoms, and set good fruit. If a tomato plant struggles to get what it needs, the whole plant suffers. learning how to perfect the tomato bed will grow healthier, heartier, stronger plants.
I’ve boiled it all down to three points. Sure there’s more, but I’m not trying to write an entire book today. Let’s stay within the shallower end of the rabbit hole for now. Tomatoes, and gardening in general, is a fickle thing and can be fairly subjective at times, so I prefer to keep things somewhat simple.
Tomatoes want Deep, Loose Soil. This is one of the more basic principles. Everybody knows that plants prefer soil with a nice, deep fluff. But, do you know that raised beds can really mess that up? Mos raised beds are pretty darn fluffy, but what about the soil under that?
Discinct layers within the soil can work almost like a barrier by encouraging roots to stay shallow. If you have loose soil in your bed and compact, Stoney, or clay soil beneath, roots tend to not dig through it. Roots tend to follow along the path of least resistance.
It can also create a very wet layer, further impeding root growth. Water does weird things in the soil. If you have two, clear abrupt layers, it tends to flow along the change in the soil. That makes the upper layer soggy at the bottom. If you have a wet or soggy layer, roots won’t like to penetrate it.
There are a few fixes for that. First off, a deeper bed is handy. It can get expensive at times, but that’s definitely a way to add more depth to perfect soil. With a wooden raised bed, you can always add another board at the top and a few more wheelbarrows full of topsoil and compost.
Another fix, or rather avoidance, is to mix your bed soil with the subsoil a bit, creating more of a gradual transition than an abrupt change. This is easier done when first building a bed, but isn’t always a large task in an established bed either. The point is to avoid a clean, abrupt change in soil layers.
When I’m making a new bed, I take a wheelbarrow of topsoil and compost and dig it into the subsoil. Then I fill the bed with a standard topsoil/compost mix. No matter what your soil looks like, this is a good practice. Eventually, earthworms will mix two layers a bit, but why not give your bed a 10-year headstart?
Tomato Plants Need Personal Space. Tomatoes are extra susceptible to a fungus called Alternaria solani. This is incredibly common in humid environments, areas with a lot of rain, and the northern midwest. I know a lot of gardeners who stopped growing tomatoes because of the yearly blight infestation.
It’s mainly complicated by lack of sun and airflow to the stem of a plant. That causes too much moisture which grows the fungus and weakens the skin on the plant stem, making it extra susceptible to infection. In the grower world, we say tomatoes need good airflow.
Space also lets the roots find all the water and nutrients they need. PLants too closely spaced will compete against each other for their sustenance. The result is stunted weaker plants. Weaker plants are more susceptible to damage and disease.
Don’t forget about having space to get in and harvest the fruits of your labor. Tomato plants are a bit fragile. If things are crammed in tight, you are likely to cause unintentional damage to plants just by reaching around and picking tomatoes. Give them some space, they deserve it.
Go Natural. Deep, Black Dirt, that’s what tomatoes need. The best fruits come from the most natural, healthy soil. I like a minimum of 10 percent organic matter in the soil. That’s enough to make it look quite black. If you don’t get too much rain, you can do a lot more than that. I like 25% in my beds.
Some people grow in 100 percent compost as topsoil. That’s perfectly alright if you don’t have too much rain. Compost can become swampy if it is constantly getting soaked. Also, unless it’s high-grade, compost generally needs quite a bit of nitrogen, calcium, and magnesium added to it at first.
You can figure out if it’s lacking in the basics with a simple DIY home soil test kit. I prefer the Lusterleaf 1602 soil test kit. Initially, a lot of fertilizer is soaked up by organic matter in the soil. it works kinda like a retirement account. When the soil fertility is matured, it will continue to feed plants for a very long time.
The humic acid-containing organic matter binds onto the loose nutrients in the soil and releases them at a constant, slow, steady rate over as much as several decades in good soil. At that point, as long as the organic matter is added, you can grow good plants with very little fertilizer added.
If you keep the soil full of organic matter and don’t use pesticides or fungicides, your soil will become a living, breathing superhouse of fertility creation and a healthy biological community of bugs, fungus, and microbes. Let your soil live. Feed your soil so the soil can feed your plants.
Yes, fungicide severely impacts healthy soil. Yes, pesticides greatly reduce beneficial bugs and microbes. Without all these functioning in high numbers, Your soil will never be healthy and you will always be playing catch-up with fertilizer. Do a good thing, go as natural as you can manage.
How Deep Should a Raised Bed be for Tomatoes?
Raised beds should be a minimum of 12 inches deep for tomatoes. Most experienced gardeners prefer at least 18-inches. Deeper beds hold more water and nutrients and allow ample space for roots to spread out, letting you create a deeper, perfect soil for your tomato plants.
I like 18-inches for tomato beds. although I prefer 2 feet deep. The plants would appreciate up to 3 feet deep, but at that point, you will have a hard time reaching the top of the plants to pick your tomatoes. that, plus the cost of building materials, topsoil, and compost, 12-18 inches is what most go with.
What Size Raised Bed for Tomatoes?
4×8 and 3×10 are the most popular dimensions for tomato beds. That will fit 6 and 4 tomato plants, respectively. The minimum width should be 2-feet. Tomato plants should be about a foot from the edge and have 2-3 feet between each plant. Tomato beds are often between 1 and 3-feet deep.
Tomatoes need space. Don’t crowd them out, it creates a whole host of problems. by overcrowding plants, you end up with less overall to harvest. Just a bit of space grows more and better food most of the time. Some professional growers do crowd them, but that takes serious science to pull off well.
As far as spacing, 2-4 tomato plants will fit in a 2×6 raised bed. 4-8 can fit in a 4×8 raised bed. tomato plants need 1 to 3 feet between them, depending on size and how well the plant is caged or staked up. Determinate (bush type) tomatoes can be planted 1-2 feet apart.
The smaller varieties (including my favorite, Betalux) are fine at 12 inches apart. Indeterminate (vining and always growing longer) plants like the Amish Paste roma and Cherokee Purple beefsteak need a good 3-feet. These plants require a lot of space because they grow super full and have huge roots.
If you grow tomatoes in pots, chances are they will be at least somewhat stunted. The smaller soil area limits root development and makes a smaller plant. Unless you use a huge pot, plants tend to always grow bigger in the ground than in a pot. I am growing some in 3-gallon pots this year for fun.
The tomato season is just getting underway in Michigan. Hopefully, I can keep the blight at bay and have plenty to sell at the farmer’s market this year. I wish you the best, God bless.
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