When preparing for a vegetable garden, the first step in ensuring success is preparing the soil.
Gareth Carter is the general manager of Springvale Garden Centre in Whanganui.
OPINION
With signs of spring blossom all around, a few days each week with warm sunshine makes one want to start planting out the summer vegetable garden.
Care must be taken, remembering it is still very early in the spring timeline and it is important that our exuberance to plant summer vegetables does not exceed the prevailing weather conditions, particularly night temperatures.
There are, however, plenty of hardy vegetables to be planted now. Here are some to get busy with:
Cabbage: Plant now in full sun in a well-drained fertile soil. Purple leaves are a sign of being short of nitrogen – feed with a sprinkle of Ican Organic Vegetable Food or Yates Dynamic Lifter.
Kale: This has become recognised as a “superfood”. Its requirements are like other brassicas (cauliflower, broccoli etc). It matures in 60-70 days and can be used cooked or fresh when finely chopped into salad or coleslaw.
Broccoli: An easy vegetable to grow. Plant in full sun in a well-drained, fertile soil. Be wary of slugs, snails and caterpillars. Broccoli matures to its best in 40-70 days, faster than cabbage and cauliflower. Plant 30-45cm apart. Most broccoli will continue to produce an abundance of shoots after the main head has been harvested so don’t be hasty in pulling out the plants.
Cauliflower: Plant in full sun in a well-drained, fertile soil. As with cabbage and broccoli, slugs, snails and caterpillars can be a problem but are easily treated with slug pellets and Yates Success. As your cauliflowers start to develop, snap some outside leaves over the heart to prevent burning and discolouration from the sun.
Celery: The flavour of homegrown celery is hard to beat. Plant 20cm apart, water and feed regularly. Matures in 100 days.
Lettuce: There are a number of varieties available including the hearting and frilly varieties which you can harvest a leaf at a time, allowing the remaining plant to keep growing. Lettuce can be grown in pots and troughs if you are limited for space and, of course, in the garden. Plant in fertile, well-drained composted soil or potting mix. Space 30cm apart, water and feed regularly. Good also in a glasshouse.
Spinach: Has become very popular, it grows easily like silverbeet and will be ready to start harvesting in six to eight weeks.
Silverbeet: A very tough vegetable that requires little attention. Also in stores is a coloured selection which has stems shaded red and yellow tones. A colourful addition to the vegetable garden and often grown in the flower garden, these varieties taste the same as the traditional silverbeet.
Carrots: Best grown from seeds and sown directly into the garden. They like to grow in nitrogen-poor soil, so a good tip is to plant after a crop of lettuces or other varieties that will have depleted the soil’s nitrogen levels. This is the same as with growing parsnips. Avoid using fertilisers with high nitrogen levels which will cause the carrots to “fork”.
There is more that can also be planted now and is available in stores in punnets including onions, spring onions, garlic, parsley, coriander, celeriac, rocket, spinach, mizuna, Chinese cabbage (tatsoi), broccoflower, chicory and more.
Tomatoes and other heat-loving summer vegetables, such as capsicums, chillies, courgettes, cucumbers and pumpkins, are all available at garden centres now. Many are planting these out now into glasshouses, cloches, pots and in sheltered parts of the garden where protection can be given from any late frosts and cool overnight temperatures. For those with more exposed garden situations, it is best to wait a week or three to plant your first tomatoes, depending on weather conditions and soil temperatures. Generally in Whanganui, the last week of September is regarded as a safe time to start planting tomatoes outside. To be successful, night temperatures are best maintained above 10C. The same timing and conditions apply to growing beans and corn, which are best sown directly into the garden bed where they are to grow. The most common failure with beans is sowing too early when the soil is not warm enough.
Preparing the soil
When preparing for a vegetable garden, the first step in ensuring success is preparing the soil. The removal of weeds is imperative. If the area is infested with oxalis, paspalum, couch or another invasive rhizomatous spreading-type weed, you will need to use a systemic weedkiller to ensure thorough removal of weeds, otherwise you will likely have a losing battle with your vegetable garden. Many weeds will be able to be successfully cleared by hand and even dug into the soil to create more organic matter. If you are unsure whether the weeds you have are invasive, you can bring in samples to the garden centre and check with the staff.
Feeding
Depending on the soil type, add a rich compost (not a cheap filler of pine bark called compost). Quality ones such as the poultry-based Ican Premium Compost and Easy Earth Compost are highly recommended. A balanced fertiliser such as Ican Organic Vegetable Food is also a great product for use before planting and as a side dressing later.
These products will help with both soil structure and fertility which need to be addressed regularly for a successful vegetable garden. Vegetables take a lot of nutrients from the soil so ongoing regular additions of products such as compost, Tui Sheep Pellets and Ican Organic Vegetable Food will replace these as well as producing a more friable soil suitable for vegetable growing.
Most vegetables prefer a neutral pH to alkaline soil i.e. pH 7-8. It is recommended to dust the soil annually with Garden Lime to maintain the slightly alkaline soil and improve the soil structure. An alkaline soil increases the availability of many nutrients and makes them more readily available for plant uptake.
Vegetables in pots
A great way to get vegetables growing before the weather is warm enough for outside planting is to start them off in pots. Try growing an early tomato in a pot. It can be a great way to get ahead of the game and allows you the option to move it inside if the weather turns cold. Tui has brought out some excellent Tomato Tubs which have a water reservoir and support frame. I use these myself for cucumbers, and in the cooler months for sugar snap peas, and they are excellent.
Growing vegetables in pots is great if you are limited in space. Container vegetable growing is increasing in popularity with specialist potting mixes such as Tui Vegetable Mix for general vegetable plants, as well as specific blends such as Tui Strawberry Mix and Tui Tomato Mix.
The key to growing in pots is watering and feeding. When the plants are getting large and the roots have filled the pot, a warm day will dry these out quickly. At this point, the addition of a saucer to the bottom of the pot can help or simply half-submerging the pot into a garden bed so it can suck up water from the surrounding soil through the drainage holes is another idea.
As the plant is limited to the nutrients in the potful of mix, these can be quickly exhausted. Fertilising little and often, reducing the opportunity for the leaching through of nutrients, gives the best results.
So give it a go - growing your own vegetables is rewarding and fun.
For more gardening information visit www.springvalegardencentre.co.nz.
Opinion: It's time to plant cold-sensitive summer vegetables.