Early Spring Marketing Using Unheated High Tunnels

Courtesy of Adithya Ramachandran, Kaleidoscope Vegetable Gardens, Dundurn SK

Most farmers underperform at early spring markets. SPIN-Farming is based on generating strong cash flow by targeting $1,000 weekly sales – in late April or early May – regardless of your growing zone. To do that you need to ignore conventional gardening practices, and get into production early, in volume. Adithya Ramachandran’s Kaleidoscope Vegetable Gardens, is in zone 3. Here is what he went to market with May 7.

SF photo fb early spring market Adi

Adi is using unheated high tunnels..and improving his production strategy all the time. Read below.

This spring has been an interesting learning experience. There are some things I would do different next year, including increasing my staggering time for radishes, and a greater focus on beets, green garlic and kohlrabi to target late spring sales.

Something else that I would like to try out next spring is an early planting of broad beans for bean production. I noticed that the ones I seeded in March were flowering now. However I tilled them all under because they were planted densely for shoot production (I didn’t get around to harvesting them all), and they wouldn’t have done well.

I also plan to diversify my spring sales next year with tulips.

Find out how backyard farmers get off to strong spring production and sales in early spring in the SPIN online support group. Receive free trial membership with the purchase of any SPIN guide. 

Become Your Own Weather Forecaster

Courtesy of Adithya Ramachandran, Kaleidoscope Vegetable Gardens, Dundurn SK

High tunnels require farmers to become their own weather forecasters. In the Saskatoon area, tonight’s forecast low is -13 C (8.6 F). That’s a little too cold for most cool-season crops, so we spent part of last week laying down row cover – 8000 sq ft of it. The cover also accelerates germination.

I’ve kept temperature records in past seasons to determine the effectiveness of row covers. Based on variables such as afternoon soil temperature at a standardized depth, number of layers of row covers, soil moisture status, and height of row covers above
plants, I came up with a few formulas for determining what the overnight low will be.

For example, today’s soil temp. at the 4′ depth is 10 C inside tunnels. I expect it to rise to 14 C by late afternoon. 14 – (-13) is 27. For a single layer, I use a factor of 0.35. 0.35*27 is 9.5. 9.5 + (-13) is -3.5 C (26 F). That is my forecast low underneath the row cover.

For double layered row cover, I use a factor of 0.45. That gives me a forecast low of -1 C (30 F). Sunflower greens are the only crop to get double cover – all other cool-season crops should be fine with one layer.

SF photo guest blog Adi weather forecast


Planting Plan for an Early Spring $1,000 Market Week

Courtesy of Adithya Ramachandran, Kaleidoscope Vegetable Gardens, Dundurn SK, Canada

It looks like spring is arriving early this year in Saskatoon. My first plantings in high tunnels typically go in during the 4th week of March, but I may be able to plant a little earlier this year. Therefore now is a good time for me to start transplants of beets, chard, kale and spinach. In early March, I will turn on my irrigation system and water all my tunnels heavily as they tend to dry out over the winter. Irrigation also speeds up the thawing process inside the tunnels. I also give myself an early-season workout by rolling in wheelbarrow-loads of snow for extra moisture.

SF photo guest blog Adi spring planning


Direct-seeded cool-season crops such as turnips, kohlrabi, radishes, onion sets, dill, cilantro and (more) spinach will go in after the transplants on a staggered basis. Later in April, I will also seed Quick Greens such as sunflowers and broad beans. The combination of all these crops will allow me to target at least a $1000+ marketing week in early May. For that week, I am targeting the following at $3 per unit, or 2 for $5. Because demand is high in spring, I usually don’t offer a 5 for $10 deal.

  • 75+ units of radishes
  • 75+ units of scallions
  • 75+ units of spinach
  • 75+ units of kale
  • 50 units of Quick Greens
  • 50 units of other greens (baby chard, baby beet greens, turnip greens or salad mix).

In mid-April I start transplants of warm-season crops (peppers, eggplants, tomatoes) for my summer relay. Unlike with cool-season crops, I avoid taking risks with these crops and always wait until early June to transplant into tunnels.

Need help with your crop planning? Purchase any of our guides and get free trial membership to the SPIN forum. There, you can pick the brains of the most successful backyard farmers today – like Adithya.

Winter Markets Keep the Cash Flowing

Courtesy of Wally S., Wally’s Urban Market Garden, Saskatoon SK

My operation in zone 3 Canada has been a year round one for many years. Now I’m starting to hear from other SPIN farmers who are usually trading their tillers for a snow blowers about now, that winter markets are booming, and that they, too, plan to keep production going.

For instance, a nursery owner in Minnesota is setting up a room to do 36 10×20 trays indoors under lights, and is planning to provide microgreens to his customers from November to May. He wants to know what kind of yield to project from each 10 x 20 tray, and the pricing he should set.  Here’s what I suggest:

  •  Try doing about 10 trays per week for starters.
  •  Think about adding micro radish to the peas for a salad mix. Very popular. Can also sell them as stand alone greens.
  •  I get about 1/2 lb. of micro radish per tray. About 1 lb. of pea greens.
  •  Stay with SPIN’s mix and match pricing of $3.00 2/$5.00, and unitize accordingly, with the idea of targeting at least $20 of revenue per tray. [Note that in some markets SPIN farmers are reporting they have been able to push SPIN’s pricing benchmark to $4 or 2/$8].  
  •  To see if you can save on costs, try growing without lights initially, just room light.
  •  Add lights, say to a max of 8 hours per day, and observe what it does for your production, and determine whether you need them.
  • Some commercial growers grow pea greens/micros in darkness, to get a yellow looking product, which chefs like.

DDG5 photo 45 DSC00574

There are many ways SPIN farmers can continue to make hay while the snow flies. Here are the SPIN guides that can give you some more ideas on how to keep your cash flow going during the winter months:  Indoor Farming with MicroGreens  Four Season Marketing


Squash Need Heat

Courtesy of Brenda S., Thompson Street Farm, Glastonbury CT

I’ve only been growing commercially for a few years (but have been hobby gardening for 16 yrs) and live in central CT. I still have so much to learn.

Last year we built a 14 x 24 green house. We built 2 raised beds and filled them with organic compost/peat and soil mixture. Our first crop was tomatoes, and we had a great harvest – although the summer was very hot (temps over 100 for weeks) and the tomatoes loved it. I had no leaf curl – although I did notice some of my plants have leaf curl this week. Its been super hot for days then it turns super cold and rainy for days.

I cant grow squash here unless its hot and dry. Squash are heat lovers and if your temps are cooler than normal it maybe too cold for them. I’m not sure what you can do other than drop your flaps and see if you can warm them up a little. If you’re hot – well I’m not sure what to say…other than check your soil????

Because of our cooler than normal temps I purposely delayed starting my tomatoes. We will see if we have a good year. I may not have tomatoes by the beginning of July but I’m hoping I will have product well into November when everyone else is done. Time will tell.

DIY High Tunnels

Courtesy of James K., Virtually Green, San Francisco, CA

A good source of practical ag info about high tunnels is the organic.kysu website page: http://organic.kysu.edu/CurrentProjects.shtml

It covers a lot of things of interest to SPIN farmers, including info about high tunnel construction, operation, energy efficiency, pest control, etc.

By the way, their peaked high tunnel design helps reduce problems with snow loading, as well as with condensation drip from the interior apex curve of half-hemisphere shaped high tunnels.

Their high tunnel design is 30′ x 40′ but can scale.

My friend Mike Bomford leads much of the research and field extension work of the KYSU sustainable ag program.

For those of you considering building high tunnels that are large and to last for a good number of seasons you should consider making your high tunnel out of steel pipe. There are a number of good steel pipe hoop bending tools out there that make the job easy and quick. You end up with a strong greenhouse that has the structural strength to handle attachment of interior fans, shades and lights (within reason).

You might modify any high tunnel design to bend half hoops instead of full hoops, with the last couple feet of each half hoop being straight to attach to a ridge beam and create a peaked roof. A peaked roof also makes it easier to build in ceiling vents if you need the ventilation in hot weather.

You might also consider straight sides and straight roof, using the pipe bender just to bend the wall- roof elbow (at the top of the sides and bottom of the roof): this increases the interior greenhouse air volume a bit and makes the interior edges of your planting area a bit easier to work. Here’s a couple high tunnel hoop bending tool sites:



DIY Heat Mat

Courtesy of Richard E. MT

When it comes time to sprout seeds, it is warm enough that I don’t need my electric blanket so I use it for seeds. I fold it to fit the space needed and cover with plastic or tarp. I do it in my basement and turn off the blanket when seeds are sprouted, after about 7-10 days. Ambient temp is about 55 degrees.

I put up shelves out of scrap lumber using screws so it is easy to disassemble and store. The bottom of each shelf supports a light on a small chain to make it easy to adjust for the shelf under it. The secret is bright light so you don’t get spindly plants. I start about 1,152 plants, mostly tomatoes and peppers, this way and it has worked well for us. The cool ambient temp makes hardening of the plants easy as you put them outside.

Heat Mat A Good Investment

Courtesy of SPIN farmer Mike B, Iowa:

I don’t think you can go wrong with a good heat mat. You are paying for the ability to be able to control the temp. to within a few degrees, as well as for the amount of space you want to heat for seedlings. I’m growing on about 1.5 acres and have a heat mat that
is 24″x 48″,  and it was a great investment. I went for the slightly larger size ($150.00) knowing that I could always grow into it.