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Growing Tomatoes in Seattle with Success!

July 31, 2008

Anyone who gardens in Seattle knows that tomatoes can be difficult to cultivate successfully. I’ve lived in the South East and the South West of the US, and in those long, hot summers there’s no stopping the bounty of ripening tomatoes all summer long. As I’ve come to understand that Seattle summers are late to start and sometimes quick to finish and always variable, I’ve experimented with tomatoes — sometimes successfully and sometimes not.

One of the first things I’ve learned is that putting out tomato plants early usually means the plants will fail or flounder at the very least. Since our temperatures fluxuate so much in late spring and early summer, tomatoes just aren’t happy in the ground until quite a bit later than many other places. Many think of mother’s day as a good “rule of thumb” marker for getting things into the garden. I like to go a bit later with tomato starts and aim for mid-June. Just to be clear, this is when I put good-sized start plants into the garden. It is not the time to start seeds in the ground.

Because I just can’t wait to get tomatoes in summer, I do like to cultivate my starts earlier than June. I’ve had great luck putting starts into the ground in my hoop house where the plastic covering keeps the plants protected and warm. When I’ve had access to a green house, I’ve kept my plants there, potting them up every few weeks until I take them outdoors to a protected location for a week or so before putting them into the ground. (I don’t want to move them straight from the warm, hot greenhouse to the ground. I put them outside for a bit on my protected, somewhat warm west-facing front porch to “harden them off”…aka get them ready to be in the garden dealing with nature.)

This year I put up a small, inexpensive plastic-covered green house on my back patio. It has allowed me to do quite a few things that I never have before. This includes harvesting a very large slicing tomato in mid-July!

Early Girl Tomato Blooming in May 2008

Early Girl Tomato Blooming in May 2008

In April I purchased one of the first 4″ Early Girl tomato starts I saw on the market. I immediately potted it up into a 1 gallon container and grew it in that for about a month. Then, in May, I potted it into a 5 gallon container into which I inserted a small tomato cage. By April, the tomato had begun blooming and it was warm enough that I kept my greenhouse door open most of the time (some nights I did zipper it shut if it was going to get cold). The pollenators began zooming into the greenhouse (along with slugs and other annoying pests), and by June I had several green tomatoes on my Early Girl (as well as a few other tomato plants I’d since added to the greenhouse.)

Early Girl Green Tomato June 2008

Early Girl Green Tomato June 2008

The other tomatoes I’d added include a favorite easy-ripener for Seattle called ‘Stupice’, a couple of determinate Romas called ‘Bellstar’, a patio whose name I don’t recall, another called ‘Fullness’, an insane indeterminate called ‘Moskovich’  and an odd-ball just for fun called ‘Black Krim’.  I picked all but the patio up at the Tilth Edible Sale earlier this spring.

I moved the patio tomato onto the patio in June, and it is filled with miniature beefsteak shaped tomatoes that are starting to ripen as of the end of July. I moved one ‘Stupice’, ‘Fullness’ and a ‘Bellstar’ into my beds in mid-June, which it seems still shocked them a bit this year. They are flowering like mad, but it seems with my reduced pollenators this year that fruit-set is a little slow on all but the ‘Stupice’, which has some ripening fruit as of the end of July.  The ‘Bellstar’ in the garden is mostly full of flowers and has yet to form fruit. Black Krim is starting to set fruit, but it isn’t doing much. The Moskovich was in the greenhouse doing nothing but putting on green growth, despite the reduced Nitrogen diet I provided. I moved it out of the greenhouse this weekend and staked it and cut it back hard. We’ll see what happens.

Early Girl Ready to Harvest Mid-July 2008

Early Girl Ready to Harvest Mid-July 2008

So, what’s next? Well, I’ll be bringing in tomatoes regularly from my patio and my stupice in the next few days. Early Girl looks to start ripening more fruit too soon. She is definitely a charm, and I will grow her again and again in years to come (in the greenhouse). You see, she gave me this enormous tomato two weeks ago — mid-July, which is, in my experience, rare in Seattle.

Oh, and one last note…my ‘Red Robin’ cherry that I grew indoors last winter continues to fruit and flower in the greenhouse. I cut it back hard and fed it bone meal, which seems to have really re-invigorated it. The plant is a year old now and has some tough woody stems. I hope to keep it going indoors again this winter…along with a few companions so I can harvest more than I did last winter.

And, just to get a little ahead of myself so you have this tip handy as your tomatoes fill up with lots of blooms and then green fruit that seems like it will never ripen here are some tips to force the fruit to ripen for you:

  • Don’t use a lot of nitrogen fertilizer after the plants start setting fruit. The nitrogen will encourage more green growth and may reduce the fruiting and flowering. (That being said, they do need some nitrogen.)
  • Cut out side shoots regularly, especially on indeterminates. This will encourage just a few shoots that will focus on flowering and fruiting.
  • Cut out every other set of flowers, especially on indeterminates, after you pass summer solstice. Tomatoes will try to grow as though they can survive our winters. We need to help them curtail their enthusiasm if we want to harvest their fruit. Reducing blooms will help the plant focus on fewer blooms turning into more fruit for you.
  • After fruit is set, start cutting back on water and by late August/early September start cutting back the tips of the plants (to a node) and cut out all the new flowers. It is unlikely (except on cherries) that flowers formed in August/September will ever give you fruit. They draw energy from the plant and discourage the existing fruit from ripening. By stressing the plant with reduced water and cutting at it, the plant will decide to try to protect the fruit it has formed already and focus on ripening that up for you!


  1. rhaglund says:

    I owe an apology to one of my readers who shared some additional information in response to this article. Somehow I managed to delete your comment and now I can’t retreive it. If you happen to read this, please share again. I appreciated that you reminded us to add calcium to help with flower set and reduce brown rot on our tomatoes. I was interested in the other information you shared, but alas I’ve lost it. My bad. Please share again if you have a moment.

  2. […] for writing in & good luck (and good eating). For more on growing tomatoes, look here. rhaglund posted this entry on Saturday, August 2nd, 2008 at 10:57 am. Posted in the category […]

  3. I just started growing tomatoes outside and have no idea what I’m doing so thanks a lot for your advice. I talked to some local gardeners and they said pruning was everything and it seems that you agree. I’m growing Brandywines and Champion VFNT. The Champions I got locally and were about a foot tall when purchased. They’ve taken off lately (as far as a plant is concerned, not as a producer of food). The Brandywines I bought in eastern WA and were about 2 ft tall when I put them in the ground. Needless to say they were very surprised at the change in weather for about 3 weeks but have now taken off too.

    Have you played with aeroponics at all? I’d really like to have nice tomatoes in the winter when the store only sells bad ones for $3/lb.

  4. I have not grown aeroponic or hydroponic tomatoes. However, I have found a variety of cherry that grows okay indoors in winter. More on that here.

  5. Annie says:

    So far I’m a tomato failure. I planted 4 very healthy plants, 2 san marzanos, and 2 early girls. They have great soil, they’ve been given tomato food (foul smelling kelp stuff), and have been caged, staked, pruned, and even rotated and moved around my porch for maximum sunlight. They get about 5-6 hours a day. 1 of them went limp last week, and I think I have another one on the verge. 1 san marzano, and 1 early girl. I don’t see any pests, diseases, etc. Any thoughts? I thought I was doing everything right. Maybe they’re getting too much water? I haven’t really been watering them becasue it rains so often, but when the soil gets dry, I definitely soak them.

  6. Annie, thanks for writing in. Sorry to hear you’re having tomato frustration. If you’re in the Pacific Northwest, you aren’t alone. Some of the best veggie gardeners and farmers I know are struggling here this year. If you’re in a warmer area, it may simply be too hot for your tomatoes. It’s a balance.

    As to why a plant went limp…that’s a tough one. Too much water can be as bad as too little. Plants need air around their roots as well as water. Only water when the soil isn’t moist. If you let it dry out completely, the plants may become root stressed. (It sounds like you have them in pots, right?) Also, too much fertilizer can also become problematic. So be sure you aren’t over fertilizing.

    And finally, 5 hours of strong sunlight a day may not be enough. Ideally, veggies get a minimum of 6-8 hours of good light during the growing season to produce. Given how this year is going, that’s a tough number to meet. I’ve gotten a couple of cherry tomatoes as of yesterday, and I have several green tomatoes, but to be honest pollination isn’t great this year. Keep trying. Do your best. And, if the plants fail, get down to your farmer’s market and support a local farmer by buying the great tomatoes they’re likely to be selling.

    Good luck!

  7. Denise says:

    Hi, I’m south of Tacoma, novice gardener, trying tomatoes for the first time this year. I have several starts of two different kinds of heirloom tomatoes. I am repotting them for the first time, and wondering if I still need to keep them inside or if I could put them on the back porch covered in plastic (I think I could rig up a sort of greenhouse with some house-covering plastic I have). They are taking up a lot of room in my kitchen!

  8. Denise,

    Thanks for writing in. I totally understand about being over-run with tomato — and other — starts this time of year. My dining room is a jungle. I have begun moving some of the tomato starts out into my unheated greenhouse, but I did this slowly and moved them out on a relatively warm couple of days to allow them to acclimate slowly. I lost a few along the way, but there are more than enough still indoors to make up for the losses. That’s why I always seed more than I’ll ever have room for!

    Also, I’m growing cold hearty varieties. They come from stock that is designed for colder days & nights. One of them even came out of Siberia!

    So, here’s the thing: If you’re going to put them out now, be sure they go somewhere protected and a bit warmer. Check your seed packet or look online to be sure the varieties you’re growing do stand up to cold. Last night, in my greenhouse, it got into the 30s. That’s cold for tomatoes. And, you might keep a few indoors as your backup plan as well.

    (The weatherman is saying we may warm up this weekend into next week. That may be the best time to start moving things outdoors — protected of course. And be prepared, if we get a cold snap, to bring them inside. Some years I’m shuttling plants back & forth in spring. Outside during the day. Inside at night until they toughen up enough to stay out all the time. Usually mine don’t go into the ground until May at the earliest and then they’re still protected under hoop houses for much of the summer, most years.)

    Best of luck!

  9. Dana S. says:

    I’ve practiced most of your tips and had good success with stupice and a few other varieties of the last few years. Each year of learning, I would adopt a new tip and last year was the tip of reducing water in the end of summer. Well, a good rain shower happened one day and half my crop split! It was like a tomato massacre in my garden and I was so sad! Any way to prevent splitting because of acts of nature?

  10. Dana, Consistent watering is a good way to avoid splitting. Or, if you’re trying to cut back on the watering, protecting the crop with a vented hoop house might work. The hoop would, in this situation, sheet the rain away from the crops you’re trying to keep water off of. It could be closed when you have a rain shower coming. Good luck in the coming growing season!

  11. AngieK says:

    I just found your website and want to try my hand at my first tomato plant as well as herbs. I am likely going to be container gardening this year to see how it goes before committing my yard to it. As a first timer I’m nervous about it. Is there any variety of tomato you recommend over another for the area? I was considering San Marzanos as I’ve read they do well here with the cooler weather and fog that we have so often but I can’t find starter plants for them. Is it too late to try seeds?

  12. Angela, Thanks for writing in and good luck. I assume by “here” you’re in the Pacific NW? If so, it’s a bit late to try seeds, but it isn’t too late to give them a shot. As a new gardener, you may find buying starts will give you more success. Regardless, go for it. San Marzano can do well here, but the easiest tomatoes to try are cherry and other small varieties, which ripen the fastest. More on growing tomatoes in Seattle as well as a few varieties we like in this article.

  13. […] Thanks for writing in & good luck (and good eating). For more on growing tomatoes, look here. […]

  14. […] them outdoors (after hardening them off) once the weather is consistently warm enough to support tomatoes and like […]

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