Keep the Soil in Your High Tunnel Healthy

Unheated high tunnel, or hoophouse, production is being practiced more widely because it is a profitable way to grow and sell year round. That requires extra attention to, and management of, soil health, as this Backyard Riches member explains.

Courtesy of Adithya Ramachandran, Kaleidoscope Vegetable Gardens, Dundurn SK

One of the challenges of high tunnel production is that there is no natural rainfall to leach the soil. Although I collect rainwater, it supplies only 20% of my high tunnel irrigation requirements. The other 80% comes from municipal water. So there are three main concerns I deal with.

1. Saskatoon city water, which supplies my farm, contains 142 ppm calcium/magnesium carbonates. Every inch of irrigation adds about 0.75 lb of lime per segment. At the rate of 1? of irrigation per week for 6 months a year, this works out to 20 lbs of added lime per segment, which can raise the soil pH and cause production issues. To neutralize this, I till in 10 lbs of organic sulfur per segment per year.

2. Saskatoon city water contains 13 ppm of chloride and 2 ppm of chlorine. Chlorine reacts with soil organic matter to form chloride. Outdoors, this is leached by rainfall. In a high tunnel, this works out to 2 lbs of added chloride per segment over 6 months of irrigation. To counter this, I try to include beets or chard in the rotation at least once every two years. These crops can ‘mop up’ significant amounts of chloride.

3. Soil organic matter is consumed very rapidly in high tunnels. I add composted manure, compost and alfalfa meal at least twice per year to compensate.

SF photo guest blog Adi hoop house


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


Storage Crops – Boring But Big Moneymakers

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

One of the mistakes I now see among SPIN farmers is they quit too soon. Once you get beyond the traditional end of season mentality you can add hundreds or thousands of dollars more, to your income, without much sweat. How?

You’re probably thinking micros. Sure, they are a lucrative crop, and versatile. They can be grown indoors or outdoors. I actually find outdoor micros are more profitable once you consider the hassle factor of trayed indoor production. Pea shoots make the most money for me, and that’s all I grow now indoors.

My go-to moneymaker is storage crops. They’re not new or trendy, but they have a big impact on my bottom line. Here’s what they have going for them:

  • they are easy to grow; most aren’t bother by pests, and they don’t require much watering
  • they don’t require the TLC that micros do; storage practices are fairly easy to master
  • they are perfect for larger plots further from your home base, since they need space to sprawl, and don’t need much tending
  • they give you product to sell long after many other growers have hung it up for the season
  • they help you lock in customer relationships you made early in the season, and can forge new ones
  • no season extension gear required

Storage Crops Income Target:                                                                                         Carrots: 50 bags @ $3, or 2 for $5                                                                            Potatoes: 50 bags @ $3, or 2 for $5                                                                             Garlic: 50 bags @ $3, or 2 for $5                                                                                    Onion: 50 bags @ $3, or 2 for $5                                                                                      TOTAL INCOME: $500 – $600/week

If you want a stretch goal you can target $1,000 a week by adding crops like beets and tomatoes. Restaurants, indoor farmer’s markets, institutions or a winter CSA are all good sales channels, especially the later the season gets, because there is less competition. You can consider it like an end of the year bonus you are giving yourself. How you use it is up to you. Splurge on an island vacation or maybe that new tiller you’ve had your eye on for a few years.

SPIN photo storage crops in cooler


Here we’re looking at $xx worth of storage crops that…

SPIN photo storage crops marketing  …fly off the shelves at the end of the season because  fair weather farmers have packed it in.

Newbie SOS: How can I get an early start on the season?

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

There are many options for season extension, but if you are just starting out in farming keep it simple. Don’t bother with it. Take, for instance,  this situation.

I have 4 – 8×4 raised (18″ high) beds here at home that I can easily cover with hoops and plastic (and will probably add more). I’m thinking I should get them covered to warm and use to start carrots for early baby carrots perhaps? Or cucumbers? Or what is best use of them?

I would not recommend covering them. It’s an unnecessary hassle. I am not a big user of season extension structures. Structures are an expense and add to your workload because you have to trouble shoot them. Your beds should warm up quicker than soil, and as soon as you can turn them over with a spade, I would put in two 18 inch wide SPIN beds, and plant onion sets and garlic. These can be planted early, and do not need to be covered.

Onions would be harvestable late May for use as scallion, and then beds can be replanted to warm weather crops, such as cucumbers, which would not need to be covered that time of the year. Garlic can be planted closely, to be used as green garlic. Once harvested, say by mid June, they can be replanted to something like tomatoes.

SPIN photo book Wally watering


My backyard in the city gives me the micro climate advantage so I can work beds in early springtime and get to market with crops like green onion and garlic before lots of other farmers. I use greenhouses to start transplants, but I don’t bother with season extension structures to produce my crops.