First week in March or week 10 starting, wow, already. Another year is going to whiz by again. Just breathe and keep working! Another week of planting seeds, harvesting tulips and anemones and getting our new hoophouse ready for seedlings.
Farmer Tony has been busy in our new hoophouse #4. This week,he has been broadforking the beds, flaming off the tiny weeds, picking buckets full of rocks out of the rows and getting the beds mineralized and ready to start planting seedlings. The center row will be planted with sweet peas this week and the side rows will have a tarp on them for about a month or so waiting on lisianthus, china asters, basil and stock.
In hoophouse #2, the dusty miller is slowly growing, as is the winter stock. The scented geraniums we are trying to hold over winter are hiding under a couple of frost blankets. We have already lost several plants to the frost and do not want to loose any more.
In hoophouse #1, the ranunculus bed is nice and lush and green. If you look real hard, there are even a bud or two. The snaps are growing out of their pinch and will need to have netting and metal hoops put over them soon.
I am on schedule with our seeding but the propagation house is filling up and backing up with seedlings that are not really growing now. This house is not heated and usually is great for our early varieties to hang out and grow, harden off and prepare to be field planted. But the little guys seem to be stuck just existing and not really growing. Larkspur, lupines, stock and sweet peas are doing well but snapdragons, foxgloves, campanula and delphinium are just stuck. Not dead but not growing. WHY??? In my panic, I ask Farmer Tony, what is wrong with our seedlings?
Farmer Tony: I take solace in knowing that the 4 basic things plants need are adequate light, adequate moisture, adequate nutrients, and adequate heat to grow to their potential. In our hoop-houses we have great control on only two out of the four, fertilization and moisture. The other two are dependent on Nature. Our natural light levels are determined by day length which is really dependent on the cycle of the seasons, so this will be what it is depending on the day of the year.
This leaves the last key component, heat. Since all our hoop houses rely on the natural ambient heat generated in daytime and our efforts to conserve this heat at night using insulation board and frost blankets etc. Sometimes the best we can do for our seedlings is give them enough heat to maintain the status quo, they grow but very slowly. For the last 2 plus weeks our daytime temps have been cool in the low to mid 40’s F with most night temps around 25-30F.
There is a concept called Grower Degree Days or GDD which is a measure of heat units generated in a day that are an indicator for plant growth. The formula assumes very little plant growth in most plants if the average of the sum of the highest temp and lowest temp in a 24 hr period isn’t above 40F. As an example, suppose we have a daytime high of 45F with a night time low of 25F. The GDD formula would be (45F+25F)/2 =35. This 35 is below the base level for adequate plant growth so the accumulated GDD heat units for this day would be 0.
Our local weather station Hyslop Field is operated by Oregon State University and tracks these accumulated GDD figures as well as other interesting factors like average soil temperatures, precipitation, etc. What was interesting to note is that for the first 2 weeks of February 2018 as things were growing, flowers were blooming and all our tulips seemed to be advancing quickly, the total GDD for this period was 95. Not huge but good for cool season plants.
For the last 2 weeks of February when things slowed down dramatically from blooming to seedling growth our total accumulated GDD was 38. The bottom line is that for the last 2 weeks we only got about 40% of the heat energy that we did in the first 2 weeks of February. So yeah, our plants know this and are waiting things out.
Just as a an additional comparison the accumulated GDD for the last 2 weeks of February in 2017 was 80, and this was considered a cool wet February. For 2016 the same period had accumulated GDD of 126! So you can see things were significantly colder this year for the last half of February than it has been for several years. So if you live in the Willamette Valley of Oregon take heart, it really was as cold as you thought!
At least I can take heart that the anemone palace is still cranking out beautiful buckets of anemones.
“I grow plants for many reasons, to please my soul, to challenge the elements or to challenge my patience, for novelty, or for nostalgia, but mostly for the joy in seeing them grow.” ~David Hobson~
Until next time, thanks for stopping by…
Makes me feel much better and not alone reading this. Thank you.
Ohmygoodness! I love it when science and farming come together! Heck- farming really is science! And my true geekness is happy.
Do you grow dahlias? If so any tips for successful growing of dahlias??
Thanks for reading the blog! Dahlias are a flower that we no longer grow. We had too many spotted cucumber beetles devouring the blooms that it made it uneconomical for us to grow them organically. When we did grow them one of the keys to a strong plant was to not fertilize too heavily. They are not big nitrogen feeders. Using a slow acting organic fertilzer in the range of of 3-5-5 worked best for us applied at planting time.
Thanks for reading the blog! Dahlias are a flower that we no longer grow. We had too many spotted cucumber beetles devouring the blooms that it made it uneconomical for us to grow them organically. When we did grow them one of the keys to a strong plant was to not fertilize too heavily. They are not big nitrogen feeders. Using a slow acting organic fertilizer in the range of of 3-5-5 worked best for us applied at planting time.
Wonderful article, hey bare thank you for such a great information I really enjoyed while reading this article.
Thanks very much for this explanation! Same thing happening in my little place. But thankfully the weather is gonna be warm for a week or so anyway. Here’s to some growth spurts!