When companion planting swiss chard, you need to keep it away from melons, corn, cucumbers, and spreading herbs like mint. These plants compete for the same nutrients and water that your chard needs to grow strong and healthy. They can stunt your chard's growth or kill it off before you get a single harvest from your garden bed.
I learned this the hard way in my third year of vegetable gardening. My swiss chard garden companions that season included watermelons planted just two feet away from my greens. The melon vines spread right through my chard bed and stole so much nitrogen that my plants turned pale yellow. Within three weeks those chard plants were dead and I had to pull every single one out of the ground.
Nutrient competition causes most of these problems in your garden. Swiss chard feeds from roots in the top six inches of soil where most nutrients collect. Heavy feeders like corn and melons have big root systems that reach into that same zone. They grab nutrients before your chard can get to them. Corn drains soil nitrogen faster than almost any other crop you can grow in your backyard garden.
Cucumbers create trouble for you because they share pest problems with chard and compete for water on hot summer days. Both plants have root systems that sit in the same soil layer near the surface. When water runs low in your garden, cucumber vines win every time since they grow faster and spread wider than your chard plants will ever reach.
I made another mistake one season when I planted cucumbers next to my rainbow chard. The colors looked nice together but cucumber beetles showed up within two weeks. These pests started eating both crops at once and spread disease between my plants. I lost half my harvest to bacterial wilt that year. You can avoid this fate by keeping these crops far apart in your garden beds.
Mint deserves special mention as a plant you must keep far from your chard bed at all times. This herb spreads through underground runners that can travel three feet or more in one growing season. Once mint takes hold near your chard, those aggressive roots will choke out your greens. The mint will take over your entire bed within a year or less if you do not stop it early.
Other herbs like lemon balm and oregano cause similar problems when you let them spread in your garden space. These plants put chemicals into the soil that slow down your vegetable growth. I now keep all my spreading herbs in pots or containers away from my vegetable beds. Or I put them in a separate bed at least five feet from my leafy greens where they cannot cause any trouble.
When you need to grow these plants near each other, use proper buffer distances to protect your chard crop. Keep corn at least four feet away from your chard rows. Melons and cucumbers need three feet of space at minimum between them and your greens. Bury landscape fabric between mint and your vegetable beds to stop those spreading roots from taking over your garden space.
Knowing what not to plant with chard helps you plan a garden where every plant has room to grow and produce food for your table. Pick compatible neighbors like beans, onions, and cabbage family crops instead. These good companions add nitrogen to your soil or feed at different depths than your chard does. Your greens will grow bigger and taste better without neighbors stealing their food and water all season long.
Read the full article: How to Grow Swiss Chard Successfully
