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Understanding how day length and season changes affect crop outcomes and Season Extension


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  1. Piney
    Piney April 27, 2019

    What would you say is the minimum average soil or ambient temperatures to start/finish your season without a greenhouse/poly tunnel?

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    redshedgardens March 2, 2019

    I have tried low tunnels but can’t keep the plastic on with the wind we get so is a struggle to keep it down putting lots of bricks along the edges. It is too much work so I just went with Caterpillar tunnels.

    1. Curtis Stone
      Curtis Stone March 3, 2019

      Get row bags and fill them with gravel. They will hold them down way better.

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    olabrie February 7, 2019

    Thanks for your response. I’m really enjoying the site and value. That’s all quite clear to me. What I’m confused about is why you suggest to plant 2 beds of radishes at the same time in the spring (i.e. with the same DTMs), which will leave you with 2 weeks worth of radishes to harvest at the same time, even after having skipped an extra week to make up for the shortened DTM. Maybe I have to try.

    1. Curtis Stone
      Curtis Stone February 8, 2019

      The outcome that you want as a farmer is consistent weekly harvests. In the springtime, it’s sometimes hard to get a new harvest each week, while the day lengths are changing so drastically, so that’s why we plant a couple at the same time, because a bed of a crop can sit for an extra week without getting too overgrown, where that would never work in the summer.

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      olabrie February 13, 2019

      Got it, thank you so much for your time and explanation!

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    olabrie February 6, 2019

    One question, Curtis. Mins 9 to 11: you explain how to plan your weekly harvest. At first you say that it’s frustrating to get the harvest of 2 beds at the same time, and that this is why to skip one week of sowing. Then, u say it’s important to plant a block of radishes to not be short 3 weeks (i.e. 3 plantings). I’m confused, b/c the 3 plantings will b rdy at same time. Can you clarify please?

    1. Curtis Stone
      Curtis Stone February 7, 2019

      Make sure to pay attention to the blocks of time in green that I am showing when I say that, because it pretty much shows it there. But, basically, I’m saying that as time progresses closer to summer, the days get longer and this means that one crop you planted one week, will be ready at the same time as a crop you planted the next, because the days are getting longer and that second crop caught up to the first. So, I sometimes will skip one week of succession to make sure the harvest dates are consistent to one per week.

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    soilengineer February 4, 2019

    If the NRCS high tunnel grant gives me the choice between one high tunnel and several caterpillar tunnels, which one should I choose? I’m in South Louisiana.

    1. Curtis Stone
      Curtis Stone February 6, 2019

      I’ll address this question in this weeks Q&A.

  6. smallcityfarm
    smallcityfarm February 2, 2019

    The changing hours of daylight have an effect on plant development but is secondary to temperature. Think about it. A greenhouse has the effect of increasing temperatures and if anything, it lowers the amount of solar radiation hitting the plants. Curtis, it would be interesting to stack Kelowna’s growing degree day data against your crop yield data. I bet it lines up man.

    1. Curtis Stone
      Curtis Stone February 6, 2019

      Interesting point. I wouldn’t have any idea how to dig up that kind of data and put it to use though.

    2. smallcityfarm
      smallcityfarm February 6, 2019

      I’ll send you a spreadsheet but if you are curious… paste this in your browser:

      Change the year in the URL above to download other years.

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    Flory February 2, 2019

    Wow thank’s love this kind of technical video

  8. smallcityfarm
    smallcityfarm February 1, 2019

    Awesome, and timely. FYI any grower can figure out their local formula for crop DTM’s based on cumulative growing degree days (GDD’s) from the nearest weather station and data wrangling in Excel. Salanova takes 50 DTM in the main season (starting May-June), that equates to 600 GDD’s for my local area. Those April plantings won’t mature until they’ve accumulated 600 GDD units = takes 9-10weeks.

    1. smallcityfarm
      smallcityfarm February 1, 2019

      I wish I could share my spreadsheet calculations…

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