Plant a rainbow - vege colour spectrum

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As every master chef, marketer and home cook knows, colour has a huge effect on appetite. A colourful meal is attractive and inviting and may even trick our taste buds. But it's not just about psychology. The same pigments which give fruits and veges their beautiful colours may play a crucial role in preventing life-shortening diseases such as cancer, heart disease and brain disorders.

Including a rainbow of natural colours in our daily diet is a great way to give our bodies the best protection nature has on offer. The brighter or richer the colours, the more life enhancing 'phytochemicals' they're likely to contain.

What are Phytochemicals?

The colours and distinctive aromas of vegetables come from natural plant substances called phytochemicals (pronounced 'fight-o-chemicals'!) Plants produce phytochemicals to protect themselves but research suggests they will also protect humans. There are more than 1000 known phytochemical, including lycopene in tomatoes, carotenoids in carrots and fruits, and polyphenols in grapes.

Phytochemicals act as antioxidants, reducing the 'free radicals' that float around inside us causing cell damage. They also have a positive effect on the body's hormones and enzymes and some have an antibacterial effect. Phytochemicals are not actual nutrients, but provide additional benefits alongside the essential nutrients we get from our vegetables.


Green leafy vegetables are low in sugar, low in calories and nutrient rich. Chorophyll, which produces the green in plants, is highly regarded as a blood purifier, thought to fight infection and promote healthy digestive systems.

Green vegetables contain other pigments, including those with anti-cancer properties. Green veges to plant now:

  • beans
  • broccoli
  • cabbage
  • lettuce
  • spinach
  • kale


Growing your salad greens is easy, economical and convenient. Whether you grow then in pots or in the garden soil, fast growth is the key. Cold, dry or poorly drained conditions lead to slow growth and a bitter taste. Feed every fortnight (liquid organic fertiliser is ideal). Lettuces need sunlight, but in hot summer weather they grow best with part shade. Lettuces in pots need lots of watering and liquid feeding.

Sow seed directly into a warm soil (no less than 16°Celsius, night and day). For a continuous supply sow every three weeks for as long as there is two or three months of frost free weather ahead.


Now is the time to sow bean seeds directly into the garden soil. Dwarf beans need no support and produce high yields in a small space, ready for eating about ten weeks after sowing. Runner beans need something to climb on. Mulch with compost to keep roots cool and moist, but avoid direct contact with the stems. Yields are hampered by very high temperatures or dry conditions, so water regularly. Colourful red flowers signal the best time to apply liquid fertiliser. Beans taste best picked young and tender, and cooked the same day.


The colour in purple/blue fruits and vegetables is mainly due to as anthocyanins, which are powerful antioxidants.

Purple veges to plant now:

  • purple cabbage
  • purple broccoli
  • purple kale
  • eggplant
  • blueberries

Aubergines - Aubergines (or 'eggplants') need four to five months of summer warmth from seed to maturity. When the first flowers drop to reveal the tiny new fruit, apply fertiliser. Avoid wetting the foliage as this encourages disease problems. Plants may need staking as they become weighted down with fruit and it's a good idea to mulch with straw, to conserve moisture and cushion the fruit off the wet ground. They will also grow well in pots.

Blueberries - A great range of blueberry varieties is now available from garden centres with varieties to suit every climate. Plant them in moist, well drained soil with plenty of peat or compost added. Blueberries benefit from feeding with acidic (camellia and rhododendron) fertiliser. Plant different varieties for cross-pollination and to spread the harvest season through summer and autumn. They make a great hedge.


Lycopene is a powerful antioxidant found in tomatoes, watermelon and chillies. A high intake of lycopene in particular has been linked with a reduced risk of prostate cancer. The red pigments in beetroot and rainbow chard are betalains, the best natural food colouring there is!

Red veges to plant now:

  • beetroot
  • tomatoes
  • red capsicum
  • chillies
  • radishes
  • strawberries
  • rhubarb
  • watermelon

Tomatoes - November is the best month to plant tomatoes. For best results prepare the soil well with lots of compost. Set stakes firmly in the ground prior to planting. Keep plants well fed and watered, especially once the fruit appears. Avoid planting in the same soil as last year and spray with copper to prevent disease. Tomato psyllid is a major problem some areas. This pest can be controlled with Yates Mavrik, taking care to spray the entire leaf surface.

Beetroot - The best way to grow beetroot is to sow seed directly into well prepared soil. For faster germination, soak seed in water for an hour before sowing. Watering is important, especially over summer. Roots are ready for harvest within about two months of sowing. Globe shaped varieties are ready to eat in the shortest time, especially the baby varieties which are lovely for cooking and serving whole. Young leaves are delicious in salads and can be picked a few weeks after sowing.

Orange and yellow

There are abundant antioxidants in yellow and orange plant pigments, which include the carotenoids. There is some truth in that old wives tale - carrots make you see in the dark: Lutein is a carotenoid stored in the eye, important in preventing cataracts and age-related degeneration.

Orange and yellow veges to plant now:

  • citrus
  • carrots
  • pumpkin
  • corn
  • rockmelon
  • butter beans
  • yellow beetroot
  • golden zucchini

Zucchini from seed - Once soil temperatures have reached 16°C zucchini will germinate quickly when direct sown straight into the garden. Work plenty of compost into the soil, or use a product such as Tui Vegetable Mix if planting in containers. Moisten the soil before planting seeds. Be sure to scatter slug pellets after sowing. Alternatively plant potted seedlings available at your garden centre. Regular watering and liquid feeding will promote vigorous growth and heavy fruiting. Apply a high potash fertiliser once the first flower buds set.

Pumpkins - If you have the space, pumpkins are easy and fun to grow. In cooler climates look for fast maturing squash varieties. Choose an open sunny sheltered position. Plant seedlings as soon as possible once the soil has warmed and the risk of frost is over into well-drained, well-composted soil with fertiliser mixed in. Take care not to disturb the young roots when planting. Pumpkins grow best with a balanced fertiliser containing potassium. Go easy on those that are mainly nitrogen.


Look for these products, tips and advice at a Go Gardening Store near you.




Aubergine (eggplant)