Such a small and often thought insignificant plant, the radish is a very useful companion plant. Radish companion planting is all about continuity, one of the fastest growing plants that I know of, from seed to table in 6 weeks. Sow every month for a near constant supply of these tasty salad vegetables.
It’s worth remembering that radishes are members of the brassica family and need to be rotated with other crops accordingly. Having said that, they make a good catch crop between rows and as markers for slower developing seeds.
Radish Companion Plants
There are two main companions to grow with radishes to improve the health and flavour of your radishes.
Chervil and Radishes
Both of these plants prefer shady conditions and will flourish in cooler climes. Chervil will deter aphids, and also keeps slugs away. Plant chervil thickly amongst the radishes in part shade if possible.
Nasturtiums and Radishes
Fast growing annuals, nasturtiums will grow in any soil conditions and hold the unique place of both a repellent and a trap crop. Depending on the pest involved they will keep away due to the strong aroma from the nasturtium, or be attracted to it. Grow nasturtiums near radishes to improve the flavour and health of the radish and serve them both on the salad plate.
Radish as Companion Plants
There are many plants that can be grown in companion with radishes for health, vigour, and flavour.
Cucumbers and Radishes
Radishes deter the cucumber beetle which is the main threat to your cucumber plants. The larvae of the beetle damages the cucumber roots and the adult beetle damages the fruit. By growing radishes in companion with cucumbers you can significantly reduce the chances of cucumber beetle problems.
Squash and Radishes
The squash beetle larvae bores into the stem of the plant and deprives the plant of nutrients and water. The squash plant will die and that’s probably the first you’ll know of it. Fortunately the radish deters the squash beetle naturally, without resorting to harmful chemicals.
Grow radishes all round your squash plants for greater protection. Plus a constant supply of lovely radishes.
Spinach and Radishes
The larvae of the leaf miner is hard to eradicate as it spends its time actually inside the leaf. The only way to deal with it is to remove the affected leaves. Not a great option when your crop is a leaf crop like spinach.
Radishes attract the leaf miner so grow them as a part sacrificial crop. I say part as although the radish leaves are affected, the root will still be edible.
Melons and Radishes
As they are members of the Cucurbitaceae family, the same family as squash and cucumbers, melons are at risk from the same pests. Grow radishes to protect your melon plants.
Lettuce and Radishes
Leaf miners damage lettuce leaves in the same way as they do spinach, to prevent this grow plenty of radishes in companion to your lettuces.
Beans and Radishes
The legume family fix nitrogen in the air and so do not deplete the soil of nitrogen. For this reason grow radishes amongst your bean plants for healthy radishes.
Parsnips and Radishes
The slow to germinate parsnip and the quick to mature radish make excellent companion plants. I sow a row of parsnip seeds interspersed with radish seeds. The radish seeds germinate quickly and mark the rows making weeding easier.
By the time the parsnips are growing and need more space the radishes have been lifted and eaten.
Carrots and Radishes
For exactly the same reasons as above, intersperse radishes in amongst your carrot seed, but take care when lifting radishes as any disturbance to the carrot can attract the dreaded carrot fly.
Broccoli and Radishes
Like many of its family, broccoli is susceptible to flea beetle. Although they cause unsightly damage to the leaves of brassica plants, this is not usually fatal, the main problem is they can spread infection. Wilt and blight being the most common bacterial infections spread by flea beetles.
Plant radish as a sacrificial crop at about 6-12 inch (15-30 cms) intervals amongst your broccoli crops to prevent damage and infection of your crop.
What Not to Grow with Radishes
There appears to be some confusion on this, many sources say that radishes should not be grown with brassicas because they attract flea beetles. I consider this one of the reasons to grow them in companion, I suppose it’s about which plant you want to grow to fruition.
Hyssop and Radishes
A Mediterranean herb that grows in similar conditions to thyme and rosemary, hyssop has been cultivated for many years and was even one of the plants taken to the new world by the colonists to use as a tea. As to why it should not be grown with radishes, although many experts agree, none can suggests why not.
What is agreed on however is that hyssop is detrimental to radish growth, so it’s best to keep them well away from each other.