Gareth Winter: Don't jump the gun with your tomatoes

There are many varieties of tomatoes available. Photo / NZME.

This has been a curious spring, with generally warm temperatures but also very cold outbreaks. One frost we had in early October has left scars in the garden, with magnolia leaves badly damaged, iris buds demolished and even griselinia leaves tipped with black.

It makes me even more cautious about planting tomatoes, despite it being the traditional time to plant all sorts of summer-fruiting vegetables. It varies tremendously according to where you live. Many coastal areas will be perfectly safe but if you are growing plants in cooler, inland areas it pays to wait a week.

But there are lots of other vegetables that can be planted with surety of success, and it is also a great time to prepare gardens for the more tender crops, such as tomatoes, pumpkins, zucchini and peppers.

If you have a glasshouse, or a sheltered area on a veranda or porch, you can get a bit of a jump-start on the season by buying some plants now and potting them up to grow on for a week or two before planting. I like to have a few potted tomatoes under way in the middle of September, some of which I will keep in the glasshouse throughout the season. Others will go out out in the garden as advanced plants, giving me a flying run at getting some fruit early in the season.

Tomatoes do best in well-drained soil so I dug out a bed and popped a lot of our own compost into it, a sprinkling of lime and handful of general fertiliser too. You could use sheep pellets or something similar, but make sure it is well dug in and placed quite deeply in the soil.

Tomatoes are a bit prone to soil sickness so it is important not to grow them in the same soil year after year -- the plants will become diseased and much less resilient.

Alternatively, you could use some containers. Just make sure they are big enough to retain the moisture the plants need when growing.

No matter what soil conditions you have it is important to make sure the position is right -- these guys really need as much sun as you can provide them with, but they also need to be kept out of the worst of the wind, while at the same time allowing for good air circulation among the plants to help prevent fungus.

Garden writers emphasise the importance of putting the stakes into the ground before the plants to avoid damaging the plants.

I was caught out last year with some dwarf beans. I carefully sowed a couple of rows in the beds, separated by some lettuces, and they threw out quite long tendrils. I hit the panic button, thinking I'd been sold climbing beans instead of a dwarf variety. So I made a bamboo tent-like structure along the two rows to make room for climbing beans -- which steadfastly grew as dwarf beans.

As I was being mocked for my odd structure I explained that I had built it to hold the next year's crop of tomatoes, so this year I will be planting along the edges of this structure rather than in rows.

There are a bewildering number of varieties available now, and first-time gardeners much be a little confused as to which types to go for. I think most people nowadays grow at least one or two plants of a cherry tomato.

Sweet 100 is probably still the most favoured, but there are many other options, including those with yellow and black fruit, as well as pear-shaped varieties.

Those with huge fruit that will provide a sandwich with just one slice of fruit are known to older gardeners as the beefsteak type. There are probably better and newer varieties now -- I use big beef -- so it pays to keep a lookout for a F1 hybrid of that description.

The same applies to the more usual table variety, usually represented by the old variety Moneymaker, which has medium-sized rounded fruit.

I have been growing different hybrids instead of older open-pollinated types for years now -- they fruit earlier and more strongly. I have been using Taupo and pioneer, which are both very good.

If you can't tolerate high acidity levels you will probably want to try something like the good old-fashioned Italiano variety, with its pear-shaped fruit, or perhaps Doctor Walter which has low-acidity large rounded fruit.

When planting make sure you water the plants well before digging a bigger hole than the plant's root ball.

You can then pop them in and firm the soil before watering again.

You can plant tomatoes a little deeper than they were in the pot -- the small piece of stem in the ground will develop roots. Keep them moist and well fed.