African, French or Signet? Which type of marigold is the best variety for your vegetable garden?
Any! Yes even though marigolds come in three different varieties and so many more colour shades, when it comes to companion planting them in your vegetable garden, you can take your pick. These wonderful showy and bright flowers attract beneficial insects and repel pests from your crops. To top it all off, they are edible!
This variety of marigolds are distinguishable by their many petals when compared to French or Signet. They are annual plants and grow to be taller than the French varieties. When companion planting them in your vegetable garden, ensure that they do not shade other plants. They are best planted on the south side of your vegetable garden, or in front of tall crops like corn. Check out these varieties - Marigold Hawaii, Marigold Sierra and Marigold Crackerjack.
This variety is probably the one with which you are most familiar. These are smaller and grow only to about 30cm or so. They are great companion plants for shorter growing vegetables like zucchini but they also intercrop between tomatoes well. They are identifiable by their less densely growing petals and come in a wide variety of orange, yellow and marron colour combinations. Check out Dwarf Double Red Cherry, Bonita or Sparky seeds.
These marigolds grow with five petals shaped like a star. They are a short growing variety like french marigolds. They are not as showy as French or African varieties but are still a beautiful bee attracting addition to the garden. Of course, they grow well with the other two varieties as well, so you can enjoy the full collection of varieties.
Marigolds companion plant well with many summer vegetables, including watermelon, potatoes, eggplants and corn. But the most common vegetable garden companion is the tomato. In fact basil, marigold and tomatoes are one of my favourite companion planting combinations. Tomatoes and marigolds enjoy the same growing conditions and may protect your tomatoes against nematodes. Marigolds apparently also excrete limonene which helps to deter whiteflies from your fruiting crops.
If you have had an aphid issue in the past, plant a yellow variety. They will attract the aphids away from your crops. They also attract ladybirds, their natural predators, who enjoy a delicious aphid feast.
If you suffer from nematode attacks then planting certain varieties of marigolds can help combat this as they have a higher level of toxins through their roots which are nematicides. Petite Harmony is one such variety. There isn't a lot of research to back these claims, but if you have had issues with nematodes, then this is a colourful, sustainable, bee friendly way to try to manage them.
Thrips, leaf miners and spider mites
These three pests are not ones you want in your garden. However, they all enjoy feasting on marigolds. By planting these beautiful flowers in your vegetable garden, you may be able to sacrifice them in favour of your other edible crops.
They are very easy to manage flowers, requiring little attention. But it is a good idea to dead head your marigolds. This means when the flower has died off, you cut off the flower. This prevents fungus, like botrytis, or mould from forming and encourages more flowering.
Author: Diana Barnes, Growing Vegetable Down Under