growing tomatoes in seattle

Easy and rewarding, homegrown tomatoes can’t be beat! Home gardeners have access to many delectable varieties not found in grocery stores.

variety selection

When selecting, check the tag as to how many days to maturity. For a long season of harvest, select multiple varieties that fruit early
season, mid- season, and late-season. Determinate varieties are typically smaller, tending to ripen all at once. Good choices for canning or if space is limited. Indeterminate varieties grow as high as you let them and produce fruit over a long season.

when to plant

Tomatoes are a warm season vegetable. They need warm soil and nighttime temperatures above 50ºF with no chance of frost. You can use "Season Starter" plant protectors to get an early start. Setting them up one week before planting will warm the soil.


Tomato plants need at least six to eight hours of direct sun for best fruit production. Tomatoes need at least 18” between plants, preferably 2 feet, for plants grown upright on stakes or cages. If no support is given and they sprawl on the ground, tomato plants need twice as much room. Plants spaced too closely will produce fewer fruits and have more disease problems from wet foliage or contact with the soil.

provide support 

Tomatoes need staking or support to keep the fruit and leaves from contacting the soil that can cause disease and insect problems. Heavy duty collapsible tomato cages are a lifetime investment that fold-up for easy storage. You can also train tomato plants on poles.

Watering & fertilizing

Make sure soil doesn’t dry out. Use an organic mulch to help conserve moisture.  Calcium, an essential nutrient for tomatoes, is readily available in most garden soils. Calcium is conveyed to the plant in water taken up through the root system. Inconsistent watering can lead to a calcium deficiency during critical fruit production  causing blossom-end rot; a brown, dry, leathery spot found on the bottom of fruit. Regular, even watering can help prevent this. 

Use a balanced organic fertilizer.  Avoid high nitrogen fertilizers such as lawn food which grow lots of leaves and very few fruits. Better yet, throw a shovel full of compost around the plants every other week.

Harvest tips -

For best flavor, leave tomatoes at room temperature away from direct sunlight. If you want faster ripening put them in a brown paper bag. 

Have a bumper crop? Share with neighbors, friends, or your local food bank.