Can You Plant Tomatoes With Brussels Sprouts?

Brussels sprouts are really quite an interesting plant.  Sprouts might look like small cabbages, but they certainly do not grow similarly. Sprouts form multiple bulbs on a single, large stalk.  While this is a long-season plant that takes 26-31 weeks to reach maturity, sprouts can be harvested for months. They can be harvested from September through February depending on your location.

This is in stark contrast to tomatoes, which are sun loving warm season crops and are well-known to most gardeners. So, if you want to plant both in your garden this year, can they be planted in the same space?

Let’s take a look at the nuances of planting a member of the brassica family (broccoli, kale, brussels sprouts, etc) with a member of the nightshade family (tomatoes, peppers, eggplant).

The Long Answer

While some gardeners report that their brassicas and tomatoes do just fine near each other, conventional wisdom is that brassicas should always be kept apart from nightshades like tomatoes. There are several reasons for this. Let’s dive in.

What is Companion Planting

Companion planting has a long and scientific history in organic gardening. The concept is meant to replicate what happens in the wild. Plants mixed together yet growing beautifully. This is because an interconnected ecosystem works in harmony. All of the plants, insects, and animals in an area enable the system to be more resilient to dangerous diseases and pests.

When you think of the modern concept of farming, it looks nothing like this. In order for those sterile rows of single vegetables to thrive, they have to be treated with a host of pesticides and fungicides. We, as the consumer, don’t often see that part, but it’s ingrained in how our food is produced on a large scale.

As a home gardener, you can choose something different. You can purposefully interplant certain herbs, veggies, and flowers to create your own complimentary ecosystem.

With that being said, every veggie has different complimentary companion plants. Tomato companions are usually plants that can tolerate heat, and won’t shade them out. Brussel Sprouts tend to fare better with other cool weather crops.

Reasons to Companion Plant

Companion plants will either help a specific crop grow better or do many supportive jobs in the garden. Benefits can include pollinator attraction (which helps increase yield), pest management, shade creation, weed suppression, and more.

You can also choose to interplant because of similar growing needs. This can be especially useful if you are gardening in a small space.

Reasons to NOT Companion Plant

There are also reasons you would choose to NOT interplant certain things together. Some plants have a negative influence on one another. For example, some plants negatively influence the taste of other plants, lure in destructive insects, compete for sunlight and nutrients, and are susceptible to the same diseases.

Warm vs. Long Season Crops

One of the biggest reasons to not plant these two veggies together is that they have completely different growing habits.

Tomatoes are a warm season crop meaning they grow, mature, and produce fruit during the warm summer months. In fact, tomatoes shouldn’t even be planted until soil temperatures have reached at least 60 degrees at night.

Brussels Sprouts, on the other hand, are a long season crop. This means they are planted in the spring for a fall or early winter harvest. In fact, they can be harvested long after your first frost.

This ‘frosting’ actually improves the flavor and sweetness of the sprouts. Harvest times can run from September through February depending on your local climate.

If we look at the list of reasons to companion plant, we cannot find a match. In fact, one reason to interplant is because plants have similar growing needs when it comes to sunlight, soil, and nutrients. Simply put, these two veggies just do not fit.

Both Plants Are Heavy Feeders

Tomatoes are well known amongst gardners for being heavy feeders. In fact, there are many articles geared toward how to feed your tomato plant effectively during the growing season.

It can be a bit of a juggle since the plant needs different levels of macro nutrients like nitrogen, phosphorus, and potassium at different stages of its life cycle. For example, if you continue to feed your tomato too much nitrogen as it matures, you’ll wind up with a very full tomato bush with very little fruit.

Brussels sprouts are also heavy feeders, but their nutrient needs are a little more consistent throughout their long growing season. An organic fertilizer that’s high in nitrogen is encouraged when seedlings reach around 6”.

You can feed again when they’re about halfway grown with any general vegetable fertilizer. Some gardners recommend a constant resupply of nitrogen specifically, but in most cases, a general fertilizer (5-10-10 or 10-10-10) will do fine.

You can see that there is a difference in macronutrient requirements between the two plants. This will be virtually impossible to maintain if the two plants are placed too closely together.

But more importantly than finding the correct mix of nutrients, members of the brassica family are well known for taking up most of the soil nutrients before other plants have a chance. This will leave little left for your tomatoes. The plants may not grow to maturity and your yield will be incredibly sad.

Brussels Sprouts Can Inhibit Growth

Members of the brassica family produce chemicals that inhibit proper growth in tomato plants (along with other nightshades like peppers and eggplants). When you pair this knowledge with what we just discussed about nutrient competition, the decision to keep the two of these vegetables separate becomes quite easy.

Our Recommendation

Our recommendation is to plant all of your nightshades far apart from any member of the brassica family. We have discussed several real world reasons why the two plants don’t play well together.

While some gardeners report no issues with interplanting the two, conventional gardening wisdom says otherwise. There are certainly no benefits to be found.

If space is at a premium in your garden, consider using containers to plant either of these two vegetables. This will help ensure that the two don’t negatively impact the other.