When should I plant tomatoes in Oregon?
When to Plant Tomatoes in Oregon – In early June when the majority of the rest of the country is almost at the point of harvesting their tomatoes, be that Campari tomato, Black Russian tomato, Roma tomatoes, San Marzano, or whatever, in Oregon, you may still be wondering when is the right time to even plant your tomatoes outside.
The problem is that each year it’s going to be different. Nevertheless, there is guidance available, at least to some extent. The following table dictates the last and first frost dates for various cities in Oregon. These dates are an accumulated average taken over a 30-year period (1981-2010).
Tap the chart to enlarge
Besides following the guidance provided from the table above, another very good way to figure out when to plant tomatoes in Oregon is to find out what the soil temperature is. And the way to do that is to use a soil thermometer.
Not got a soil thermometer? You can buy one from a hardware store, a garden center, or online at someplace like Amazon. Soil thermometer’s need cost no more than around $15 and they do, in fact, play a vital role, at least in determining when to plant tomatoes outdoors. Here’s an excellent soil thermometer from Amazon:
With a soil thermometer to hand, simply poke the end of it into the soil at a depth of around two inches. If the soil temperature is still too low (below 50 degrees F), roots will fail to grow. If roots fail to grow your tomato plants will fail to grow. Plus, what has grown will become ever more susceptible to disease.
So, ideally, what you want is the soil temperature to be at a minimum of 60 F or above. If the soil temperature gets to 70 F or above your plants will really begin to thrive.
Test the soil temperature early in the morning. If it’s still below 60 F, don’t be tempted to plant your tomatoes outside.
You also want daytime air temperatures to be 70 F or above, and nighttime air temperatures to be at 59 F or above. If the air temperature is below 57 F growth will be stunted and you’ll likely not witness any growth at all.
Best Tomatoes for Oregon
Some tomato varieties perform relatively well in colder climates such as in Oregon. Early Cascade and Oregon Spring, both bred by OSU, are ideal choices. Likewise, Stupice, which is an heirloom tomato variety tolerates cooler soil conditions. Stupice also sets fruit when the air temperature is relatively low as well.
Other tomato varieties that do well in Oregon include the slicer tomatoes (for sandwiches, salads, etc.) Cherokee Purple (heirloom), Oregon Spring (F1 hybrid), Legend (F1 hybrid).
Great tomatoes for preserving and making sauces that grow well in Oregon include Roma (large cherry), Oroma, Oregon Star.
Among the cherry tomatoes that do well in Oregon are Yellow Pear, Super Sweet 100, Sweet Million, Black Cherry.
Anyway, it’s best to take any guesswork out of planting tomatoes outside. And to do that you need to know the temperature of the soil. And to know the temperature of the soil you need a soil thermometer.
More Tomato Growing Tips – When to Plant Tomatoes in Oregon
If you want to get started with your outdoor tomato transplants even when the temperatures are still on the low side you can do by investing in devices that come with a season-extending capacity. Try the Wall-O-Water ‘technique’ which works in boosting air and soil temperature.
You could invest in frost protection cloth for your tomato plants.
If you’re buying your tomato transplants go for transplants that are stocky and leafy. Don’t buy thin, leggy transplants. If you do have to buy leggy plants bury a large part of the stem in the soil (don’t plant any leaves – take leaves off). Tomato plants are able to develop roots when the stem is planted in the soil.
If your tomato transplants have been grown in a warm greenhouse you’ll need to acclimate the plants before they are planted outside if the temperature is still a bit cool. When it’s sunny, place your transplants outdoors. Bring them inside at night. Doing this over a period of a week will harden up the plants sufficiently.
Avoid planting your tomatoes in the same place year upon year. Rotation is the name of the game. Rotating tomato plants from one spot to another each year helps in discouraging soil-borne disease.
Allow plenty of space between your tomato plants when planting outdoors. Tomatoes (particularly indeterminate varieties) will benefit from a minimum of 24 inches spacing between each plant.
Towards the end of the growing season, remove the upper-most foliage of your tomato plants and remove any baby fruit. This will help to ripen any remaining tomatoes.
Mulch your tomato plants in July with two to four inches of shredded leaves or straw. Mulching around the base of the plants reduces watering splash-back. In turn, this also minimizes soil-borne disease.
Consistent watering is essential. Water deeply twice weekly. In mid summer, if your plants go dry, if your plants have plenty of fruit don’t try to compensate for lack of water. This will likely lead to cracking of the fruit. Instead of overcompensating – overwatering – provide regular moisture, as is dictated by weather conditions, every few days.