Tomato Time – Seeding and Potting Up

This week we started tomatoes in the greenhouse. These guys are going to be planted to the field around May 28th after the last full moon in May. In zone 5B, we don’t often have frost that late in the month but a couple near brushes have made me a little less cocky with planting early.

And frost isn’t the only thing that can give tomatoes a tough time. Cold soil and damp cool overcast days are not the conditions that tropical plants like tomatoes enjoy establishing themselves. Waiting till conditions are better often results with a plant growing quicker and better than a plant that has faces a lot of early challenges.

Sure, you can use row cover and perforated plastic tunnels to create a warmer micro-climate, but these ressources aren’t cheap and I’d rather do something else with my sunny Spring hours than wrestle with remay.

We seed tomatoes (and peppers and eggplants) in open flats full of potting soil. We seed 5 rows of roughly 65 seeds/row.

We mark the rows with this handy tool my co-farmer Renée built. It is designed to mark 7 rows in wide styrofoam trays for onions or leeks but we make it work in a 5-row situation

These peppers and early tomatoes are doing fine.

Now, we just seeded our field tomatoes and seed tomatoes in the greenhouse but we seeded tunnel tomatoes at the end of March. It is time to pot those babies up …

These seedlings are quite tight in their small tray – at this size they’ve just about depleted the nutrients in the potting mix. Potting them up will give them a shot of new soil and fertility. If you wait too long, the plants might be stunted and compromise future production.

Emily separates the little plants …

and delicately (but quickly and efficiently!) snugs them into the tray. We usually pot up nightshades once into 50 cell trays (10×5 cells). We sometimes pot up tunnel tomatoes into 3″ pots but don’t do this for field tomatoes.

In other news, Crop Planning for Organic Vegetable Growers is out!!! My co farmer Fred and I have been working on this book for a year and a half and are thrilled to see it published. It is available through the Canadian Organic Growers website though Fred and I do have copies also.

Also, last weekend the Eastern Canadian Organic Seed Growers Network had another great event. In one of the sessions, I applied some of the profit analysis featured in the crop planning book to seed production. I will try to write that up next week.

4 thoughts on “Tomato Time – Seeding and Potting Up

  1. Dan, your posts never fail to inspire and motivate. I have question about starting warm weather plants in the greenhouse. I started tomatoes and peppers indoors under lights in 96 cell flats last week and the tomatoes are starting to sprout. The cells are quite small and the seedlings will need to be transplanted a little earlier than I’m used to doing. Would you do the transplanting into a 4″ pot inside an unheated hoophouse if night time temperatures are around 4 degrees? What about brassicas?
    Thanks and keep up the good work.

    1. Hi Jeff,
      Thanks for the encouraging words.

      For tomatoes:
      A bigger pot will definitely mean less stress for the plant, but I would be afraid to put my tomatoes in an unheated hoophouse this early. Tomatoes really don’t like cold temperatures. Stressing the plants now can really delay you harvests later.

      Do you have any other tray sizes? Planting your plants into 50 cell flats (even 72 cell flats) will give the tomatoes more room and fertility but require less space than 4″ pots.

      If you need to get them out of you house, covering the tomatoes at night with one (maybe even 2) sheets of row cover will raise your temperature a bit. Do take the row cover off during the day.

      For Brassicas:
      These guys can take the cold nights much better than the tomatoes. Some of the heading brassicas (like broccoli and cauliflower) can produce a deformed head if subject to cold temperatures. Again, night-time row cover will make them happier.

      Lettuce, spinach, chard, alliums do fine at 4C night temperatures.

      I hope this helps,

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