You either love em or hate em.
Ok so that is just not true I for one do not love tomatoes, but I do love tomato products like salsa, ketchup, marinara sauce, etc, etc. This love of tomato products not tomatoes has led me to explore many avenues of succesful tomato production. I have seen staked, caged, free range tomatoes, greenhouse tomatoes, hydroponic tomatoes etc, etc. What I learned though all this is that there are way to many techniques for growing tomatoes and that I couldn't begin to use half of them in my personal garden. I needed something that is an effective use of space, provided good growing conditions and prevents weeds and pest damage in the most environmentally friendly way possible.
That's when it hit me, I needed to do research into companion planting for tomatoes. Using the right companions in my garden I could solve all the problems that face a tomato and grow even more veggies at the same time.
Ahh the wonderful asparagus another much-loved and hated vegetable. Many of us over the years have turned our nose up to asparagus when it was offered, but lets face it we didn't know any better. Asparagus sautéed in butter has to be one of the most simple yet delicious dishes you can make and is usually a crowed pleaser.
But enough of that you are here to find out why asparagus makes a good companion plant to tomatoes. Well like most good pairings this is a two-way street with the tomato helping the asparagus as well as the other way around.
The tomato produces a chemical called solanine which does "something" to the asparagus beetles. I could not find something definitive that stated what solanine does to them but the world of the Internet seems to agree that solanine will solve your asparagus beetle problems. If you know of or have a reputable reference of this fact please let me know in the comments.
Now again according the world of the Internet the asparagus plant produces another natural chemical the name of which I could not find that kills nemetodes that afflict tomatoes. How the chemical does this or what is called I could not find. So again if you know a good reference for this let me know so I can add it. 
Who doesn't love chives?
I mean really, this versatile herb can be put on salads, meat, potatoes pretty much anything you want to spice up with a little garlic or onion flavor. If you don't love chives you must just be weird.
Just kidding by the way you are entitled to like or dislike whatever you want. Anyways to get right down to it why do chives make a good companions to tomatoes? Well to start off they are perennials like asparagus and very difficult to kill (speaking from experience here). That means they will always be there before, during and after the tomatoes life. But what is it about chives that help tomatoes. Well you are a fan or chives you might already know that chives produce a fairly strong odor. Well to tomato aphids that smell is intolerable and it actually drives them away. So chives placed properly in and around your tomato plant can essential create a scent barrier to aphids.
So to recap chives make a wonderful companion to tomatoes because,
- They are perennial
- Hard to kill
- Provide flavorful accents to many different types of food
- Create a scent barrier that drive tomato aphids away
This one had me stumped for a bit as I thought about it. What could carrots and tomatoes possibly like about each other. Well when you look at some of the basic requirements of the two plants the answer begins to become a little clearer.
Carrots are a cool season, deeply rooting root crop.
While tomatoes are a warm season fruiting crop that like to spread out if it can. They also like loose well draining soil that can require a lot of work to maintain.
Well for companions these two do make an unlikely pair, but they do help each other out quite a bit. As the heat loving tomatoes grow they begin to shade the cooler temperature loving carrots which greatly appreciate the extra shade. They also excrete that familiar chemical solanine which kills insects that might otherwise damage the carrots. They carrots return the favor by losing the soil around the tomatoes providing avenues for better root growth for the tomatoes.
Also on the plus side these two use the garden space for its full season as the carrots can be put in early and you usually let the tomato go as long as it can it so it works out pretty good I would say.
Parsley a popular culinary herb that is used extensively in kitchens around the world. It is cold tolerant but cannot withstand harsh winters found in much of the US so for the purpose of this article it shall be considered an annual. It can be planted earlier than many tomato crops and as such can get some good growth going before the tomatoes get really started.
What parsley does for the tomato is that it attracts predatory insects that target the tomato hornworm. It is also great at repelling other damaging insects in the garden. As a general insect repellant in the garden you can also interplant among most of the garden, just make sure to keep it away from your mint and lettuces.
One of my personal favorites, onions are a versitile and useful companion plant for your tomatoes. Like chives they emit a pungent odor which deters most pests from even getting involved with them. You will want to space onion plants out however and not plant them in solid blocks as they can become infested with onion maggots which will reduce there usefulness to you and well as potentially ruin the onion crop.
One thing that must be mentioned is that there is very little to none scientific evidence that companion planting actually works like it is advertised. Most of what you will read stem from he said she said kind of evidence and as such must be taken with a grain of salt.
As much as it pains me to admit this article is much the same. I tried to find actual evidence that support the claims or organic gardeners around the world and I couldn't really find any. But despite all that it wont hurt to give it a try in your own garden if you really want to.
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