Growing Tomatoes

Photo by Jeremy Keith via Flickr/Creative Commons

Delicious, versatile, juicy, nothing says summer to me like fresh tomatoes still warm from the sun. As the song goes, “there’s two things money can’t buy: that’s true love and homegrown tomatoes.”

One of the gardener’s favorite staples is the tomato, but it can be a finicky plant, especially in cooler climates. I’ve grown tomatoes in the Pacific Northwest for years, more or less successfully. Some years have been better than others.

tomatoes on the vine
Photo by Tam Tam / Flickr (Creative Commons)

If you have struggled with tomatoes in the past, or aren’t sure how to get started, here are some basic steps, tips, and tricks for getting a bountiful tomato harvest.

Tomatoes And Your Climate

a ripe tomato ready for harvest in Meadowood’s Edible Learning Garden.
Photo by Theresa Jefferson / BLM Eastern States

One of my best friends grew up in the Rocky Mountain desert region of the US, and she says that tomatoes were the easiest thing to grow. Sadly, that is not the case in cooler and wetter areas, or in places with hot nights.

The climate you are growing in affects everything you plant, but especially hot weather crops like tomatoes and peppers. To know when you can plant in your climate, check your soil temperature, or consult a garden planner.

Tomatoes can only be planted when the soil temperature rises above about 55 degrees F, and they will start to suffer in the fall when the temperatures drop again. For tomatoes, the longer the growing season, the better.

However, tomatoes also fail to grow optimally if the weather gets too hot. If daytime temperatures stay above about 90 degrees F and nighttime temperatures are above 75 degrees, tomatoes will stop growing and lose their flowers, which halts fruit production.

In very hot places, people plant spring tomatoes and fall tomatoes to get two crops a year during those more moderate seasons, and don’t plant at all in summer.

These climate variables make it extra important, as always, to pick varieties that are well suited to your local weather patterns and summer temperatures! Read the information in the seed catalogs or websites closely—they will tell you optimum soil temperatures and length of growing time for each variety, and some will tell you which zones the variety grows well in.

Starting Tomato Seeds

Tomato seedlings peeking above the soil
Photo by Ramsay Thomson / Flickr (Creative Commons)

To give your tomatoes the best chance of a long growing season, start the tomatoes indoors before the garden warms up. If you are buying tomato starts to plant, skip ahead to the next section.

Start seeds between six and ten weeks before your soil temperature is warm enough for tomatoes. In the maritime Northwest, that means starting tomatoes in early April, for transplanting out in late May or early June. In my grandmother’s garden in Florida, she would have planted starts in December for planting out in February.

Choosing the correct starting time is a bit of a gamble with the weather. If you start your plants too late, they will be behind in the growing season and you will be twiddling your thumbs waiting when all your neighbors are harvest big, juicy tomatoes.

However, if you start them too early, the plants will start outgrowing their seed trays before it is warm enough to transplant them. Once the seedlings use up all the nutrients in their potted seed tray, they will start to die, and you will have lost your entire crop!

Seed Trays Or Pots?

You can start seeds in seed trays or in individual pots, in a variety of sizes. The smaller the container, the sooner you have to plant them.

Some people start in seed trays and then transplant into pots before transplanting them into the garden. The benefit of seed trays is that you use less soil and space when the plants are small, and you can choose the hardiest plants to transplant into biggest pots.

You do get bigger, stronger plants that way, but I personally think it’s too much work. I start my tomatoes in 4-inch pots and skip the seed tray step entirely.

As tempting as it is to fill your pots with soil from the garden, you will get better results if you buy potting soil. Commercial potting soil is designed to stay light and fluffy so it won’t smother small seeds, holds moisture well, and most brands are nutrient-enriched so you don’t have to worry about fertilizing your starts.

Put your seed trays or pots in a south- or southwest-facing window that gets midday light, and water regularly. Get a watering can with a shower nozzle, to help the water fall gently and not disturb the seeds.

When you are finished watering, the soil should be uniformly moist, with no water pooling on top. Too much water will drown your seeds. The soil should be absorbing all the water you give it.

How To Transplant Tomatoes

Pick your planting spot. In the Northwest, Northeast, and Midwest, tomatoes need to be planted in full sunlight.

One year I tried to grow tomatoes in a backyard garden that got sunlight between about 10 am and 5 pm. I thought that would be enough daylight, but I was wrong. The plants grew slowly, and the fruit ripened slowly also. I did get a few tomatoes off those plants but they came late in the year and my harvest was pathetic—just a few tomatoes off a dozen plants.

tomato plant
Photo by Dan / Flickr (Creative Commons)

However, as discussed here, if your area gets overwhelmingly hot summer days, tomatoes do best when planted in partial shade.

Planting In The Right Soil

Prepare your soil bed like you would for any other planting. Get your soil tested to see if it needs amendments. Tomatoes like a soil pH of between 6 and 7.

Soil acidity varies widely from region to region depending on the mineral and organic composition of the soil. You don’t need to treat your soil’s pH every spring, but you may need to amend with other nutrients.

All plants need the “big three” nutrients, nitrogen, phosphorus, and potassium, or NPK, which are often depleted after a growing season and need to be added each spring.

Add manure or an NPK fertilizer to the soil when you transplant, for added plant growth and vitality.

Placing The Plants

Follow the spacing guide on the seed packet when you transplant. Tomatoes need a lot of space to spread their leaves, between 1 and 3 feet depending on the variety. I was taught that when transplanting, you always loosen the root system to prevent rootbound starts from being stunted. However, that is more true for starts you buy at the store, which are often more rootbound than plants you start yourself.

If you started your tomatoes at an appropriate time, they should not be too rootbound, so it is better not to disturb the roots. Just put them in the ground and pat the soil around them. Tomatoes will grow roots from the stem if you bury them deep, and more roots are always better.

In cool climates, some people plant tomatoes in hoop houses, which warm the soil, protect plants from light frosts and keep them dry in the rain, which prevents blight. In very hot climates, tomatoes can be planted in shade houses.

Tomato Plant Care

tomato on balcony garden
Photo by junksignal / Flickr (Creative Commons)

Water your tomatoes regularly, whenever the soil is dry an inch to two inches below the surface. I typically water once a day in the summer, in the evening, so that the water doesn’t evaporate in the midday sun.

Tomato plants don’t like it when their leaves are wet, so drip tape is the optimum way to water tomatoes, but if you are watering with a hose be gentle and aim low on the plant.

As your tomato plants grow, they may need to be staked, once the heavy fruit starts weighing the plants down. Tomatoes varieties are either determinate or indeterminate. Determinate tomatoes reach a full size and stop growing, while indeterminate tomatoes will keep growing as long as conditions are good, but both types benefit from being staked.

Surrounding your tomatoes with companion plants may also help keep them stronger.

Trimming Tomato Leaves

To get the most prolific harvest of tomatoes, trim your tomato leaves throughout the season, to redirect growing energy into the fruit. Trimming the leaves also allows more light to reach your tomato, especially if your plants are getting bushy.

Trim side shoots, anything that’s not flowering, and any brown or withering leaves. Choose a few strong looking branches to be fruit bearing and trim others. Don’t be afraid to trim aggressively, especially early in the growing season.

I trim a just a few shoots every time I water, so that I never stress the plant by trimming too much at once. The first year I grew tomatoes I didn’t prune because I was afraid to hurt the plant, and I ended up with incredibly bushy, incredibly lush plants that shaded out their own tomatoes!

Tomato Blight

Tomatoes killed by late blight in Hawai’i. Photo by Scot Nelson / Flickr (Creative Commons)

In cool or damp climates, tomatoes and other plants in their family, like potatoes, are susceptible to late blight, which shrivels leaves, stunts fruit and eventually kills the plant. In some places, like western Washington, this is inevitable. Every year, late blight is what ends our tomato crop, long before the first frost.

These tactics may delay tomato blight:

  • Always rotate your planting location—don’t plant tomatoes, potatoes, or peppers in the same ground two years in a row.
  • Never reuse potting soil and sanitize your tools, stakes, and pots in bleach or vinegar at the end of the season.
  • If you visit a community garden or a farm, which are practically guaranteed to have blights and diseases of many kinds in the soil, always wash and sanitize your boots before working in your garden again, or use different shoes entirely.
  • During the growing season, keep the tomato leaves dry and trim any leaves that are showing signs of blight.
  • If you compost your own garden waste to fertilize, don’t put tomato or potato trimmings in it. Compost them separately or burn them.

Late blight attacks tomato plants everywhere, especially in wet years. There is no way to prevent it entirely, but you can take precautions so that the impact on your growing season is minimal. You can still eat fruit from a blighted plant until the blight attacks the tomatoes themselves!

Help! I’m Drowning In Tomatoes!

What a great problem to have! Some years it seems like I wait all spring just dreaming of tomatoes every time I make a salad, and then they all come on at once and I get totally overwhelmed.

lots of cherry tomatoes
Photo by Jeremy Keith / Flickr (Creative Commons)

Some tomato varieties produce continuously through the growing season, while others set all their fruit at once. The seed packet will tell you which type you are growing. If all your tomatoes come in at once, you are going to need some tomato recipes!

Almost every dish is improved with fresh summer tomatoes. Make a batch of tomato sauce and check out our guide to canning for tips on pressure canning—the best way to preserve tomatoes.

Serve them with rosemary and salt as a side dish, or make them the centerpiece of a fresh tomato bisque. Make a tomato sandwich, southern style, just tomato and mayonnaise on good bread. And of course, one of my favorites of the summer garden—ratatouille, which uses all the hot-season crops. (See my recipe below.)

But what I always do with the very first tomato of the year is slice it up and eat it plain, because homegrown tomatoes shine all by themselves.

Final Words On Tomatoes

Tomatoes are at once finicky and remarkably hardy plants. They recover well from stress like drought, so don’t lie awake at night trying to remember if you watered the tomatoes.

If your first year growing tomatoes is not all you hoped it would be, try again, with a different planting time, more vigorous trimming, better soil amendments, or a hoop house.

Depending on the weather patterns of the year, you will have boom and bust years with tomatoes like with all crops, no matter where you live. If all else fails and you don’t have good luck growing tomatoes, my best advice is to get friendly with someone who does.

My Ratatouille Recipe


Slice 2 zucchini, 1 eggplant, and 3 tomatoes, and toss in olive oil and salt. Layer on the bottom of a pan and cover. Roast in the oven at 350 degrees until fork-tender.


Roast 1 lb. peppers and 2 lbs. tomatoes in the oven or sauté in a skillet. Put in a food processor with ¼-cup olive oil and season with salt, rosemary, thyme, sage and marjoram to taste.

Assemble And Serve

Pour sauce over the roasted vegetables, and put back in the oven until sauce bubbles. Some people top with shavings of a hard cheese like pecorino romano. Serve with a garden salad.

Written by Lucia Wyss

Lucia Wyss splits her life between town and country. When she's not in Olympia with her garden, she is helping her partner at Hidden River Farms raising pastured pigs and growing organic grain and veggies.


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