It is time to plant tomatoes when the soil temperature reaches 60 degrees Fahrenheit or higher. You can plant tomato seeds in Seattle from April to early May. If you are starting seeds indoors, planting usually occurs about six weeks earlier. Wait for warm sunny days and plant your tomato seedlings outdoors after the danger of frost has passed. Let’s look at when to plant tomatoes in Seattle.
The Best Time to Plant Tomatoes in Seattle?
The best time to plant tomatoes in Seattle is in April or mid-May. If starting your plants indoors, you can plant the seeds in March and keep them in a warm location. Indoor plants can be moved outdoors once the weather gets warmer.
It’s best to wait until after the last expected frost date, around the 17th of March¹, to plant tomatoes outdoors. What kind of tomatoes should you grow? Big beefsteak tomatoes, plum or cherry tomatoes. There are hundreds of tomato varieties to choose from, and they can be classified by size, color, shape, and use. If you want something tasty for pasta sauces, try a paste type such as San Marzano. The plants yield a lot of fruit and are resistant to blossom end rot. Indeterminate varieties can be planted at the same time as determinates, but they should be placed in a separate part of your garden.
Caring for Tomato Plants
Tomato plants should be planted in a sunny location and require at least six hours of direct sunlight. Make sure the site has good drainage and provides enough water for optimal growth. Tomatoes should be spaced at least twelve inches apart.
Now that we know WHEN to plant tomatoes in Seattle, lets take a look at HOW to best care for them.
Tomato plants require a lot of water, especially as the fruit begins to form. A good soaking once a week is sufficient, but more often if they are in very dry soil. If you have been using drip irrigation or soaker hoses, ensure that the water reaches the roots. If not, switch to deep watering every three weeks.
Tomato plants should be fertilized at least once a month with an organic fertilizer. For best results, ensure you provide fertilizer early in the spring when growth begins and once in mid-summer when blossoms are starting to form. Avoid feeding tomato plants in the fall as this will promote new growth that can be damaged by frost.
Once the fruit begins to ripen, you should pick them off the stalks or vine. If you have lots of tomatoes, try turning them, so all sides receive sunshine and continue harvesting at least every other day.
Tomatoes are ready for harvest when the skin turns a deep red color. If you leave them too long, they can lose their flavor and go wrinkly. Wash the tomatoes under cold water before storing them in a cool location.
Tomato Growing Tips
- How to care for tomatoes in winter
- How long it takes to get from a flower to a tomato
- How to get thick stems from a tomato plant
You can plant tomatoes in Seattle when the last frost has passed.
Tomatoes can be planted outdoors in Seattle between April and May. If you want to start your tomatoes off indoors, you can plant the seeds in March and transfer them to a warm, sunny outdoor location when the weather starts to improve. Make sure to give your tomato plants enough space and lots of sunlight and water, and they should do well all summer long.