The advantage of growing tomatoes in containers in a rather shady garden is that you can move the pots around to keep them in the sun, which they need to ripen and sweeten, assuming you have the strength to lift the pots or a dolly on which to transport them.
With pots you can use just the right soil mix, too, something better than ordinary garden soil, and it’s easy to control irrigation and fertilizer.
There’s one big caveat, though, and that’s proper irrigation. Never let tomato in containers dry out and then try to make it up by flooding the pot with water. It’s important to water evenly: check the soil and water every day if necessary—sometimes twice a day in hot weather. If the soil becomes dry, blossom-end rot results, which means rough brown skin and flesh on the bottom of the fruit, rendering it half edible. Too much water can result in split fruit.
Although most tomatoes in containers grow successfully, choosing the right variety is important. Determinate plants, which grow to a certain height and then stop, are a good choice. They don’t get so big that they flop over, pulling their useless tomato cages with them, as Indeterminates do.
On the other hand, Indeterminates have the advantage of setting fruit over a longer season, and will produce later into September. (Ask the nursery where you’re buying started plants, or look at the seed package if you’re starting from seed, to see what you have.) However, most Indeterminates can be supported in a tomato cage and pruned back. Keep the plant to one main stem and cut out the suckers that grow in the axils between the leaf and the main stem. This helps keep the plant under control.
Cherry tomatoes like Sweet Million cultivars bear early and prolifically over a long period of time. But
Here are some general rules about growing tomatoes in containers.
- Choose large pots at least 40 cm in diameter. Plastic pots don’t dry out as rapidly as clay pots, and are lighter. Half whisky barrels and bushel baskets are also good.
- Use a soilless mix with a generous addition of compost, or a combination of one part each of potting soil, perlite and peat moss. Add a slow-release fertilizer to the soil if you like, and a water-holding gel to reduce future watering requirements.
- If your tomato plants are leggy, plant them deep. They will develop roots along the stems underground.
- Insert a tomato cage or some kind of support at planting time, not later, when you might damage the roots.
- Move plants to gain sunlight. Tomato plants need at least eight hours of sunlight each day to mature properly.
- Water and fertilize regularly. Plants in pots benefit from frequent feeding. Give them a weak solution of a high- phosphorus product, such as a 15-30-15, about every two weeks.
- Once the fruit looks nearly mature, strip off leaves that may be shading it to allow fruits to ripen.