Growing Through the Winter

A gardener asked the following question about building small greenhouses and growing in cold weather using information from the Mittleider Grow-Box Gardens book: “Since I am in zone 3 it would be very helpful if I could have the rest of the information the article referred to on “cold weather gardening” in chapter 12 if you think I need it. Is that the information that will tell me how to double-layer the greenhouse to have a 3-to-4 inch dead air space?”

Here’s my answer, which will be helpful to anyone who is building a greenhouse to grow in cold weather.

Chapter 12 of Grow-Box Gardens does indeed show and tell you how to double cover the greenhouse. I am sorry that Grow-Box Gardens is currently out of print and unavailable. Hopefully we can figure out how to get it re-printed inexpensively enough to have it available again by next growing season. In the meantime, let me tell you a few things the book says about winter gardening in cold climates.

Seedlings should be started in warmer weather and transplanted into the greenhouse by early fall if possible, so that much of the vegetative growth takes place before it gets cold.

During the cold months plants can be maintained and harvested at lower temperatures. It is important, however, to maintain soil temperatures above 50 degrees as long as possible, otherwise the plants will go dormant.

A greenhouse is important, and it should be double-covered, with a dead-air space of 2-4″. Building the greenhouse east to west, with the north-side wall built into a hillside or against an insulated wall, can reduce heating costs significantly, and even provide some heat from the mass of the north wall.

If you’re really serious about growing in cold weather, hot water pipes buried 4-6″ deep inside the greenhouse near the outside edges will provide some heat and ward off cold from the frozen ground outside.

If it is too cold to keep the entire greenhouse from freezing, consider a greenhouse within the greenhouse to protect valuable crops.

Arched PVC frames covered with 6 mil greenhouse plastic, with a small space heater inside, can keep a row or two of plants warm enough to save them even on very cold nights, if it is inside a greenhouse already.

If daytime outside temperatures rise above 65 degrees some ventilation should be provided in the greenhouse.

Compare Mittleider Method With Commercial Produce Growers

Q.  The commercial produce growers in my area use black plastic with drip lines. They mix fertilizer in their irrigation water and pump it to the plants. What makes the Mittleider method more productive and efficient?
A.  Large commercial growers of things like lettuce, cabbage, etc., who water and feed accurately, especially those who feed regularly right in the water supply, and who eliminate weeds completely, are at least as good and productive as the Mittleider Method.  They also have very large investments in materials and equipment.
The Mittleider Method is sometimes called “the poor man’s hydroponic method” because it borrows principles and procedures from the large hydroponic, greenhouse, and field growers, and adapts and sizes them to the small family farmer and family-size garden.  And we produce great yields without the large capital investment large growers must face.
Most family gardeners don’t understand the importance of a constant water supply, just to the root zone of the plants.  They don’t appreciate the value of regular feeding with a complete, balanced nutrient, and they don’t realize how much weeds rob their garden of nutrients that are essential to the well-being of their vegetable plants.
Beyond those three principles, the Mittleider Method teaches vertical growing, with the attendant pollinating, pruning, and protection issues the hydroponic growers handle so well.
These are the primary elements that set the Mittleider Method apart from typical or traditional FAMILY GARDENING and make it SIMILAR to (not better than) hydroponic and large commercial growers.

Growing Peppers Vertically – “Poor Man’s Hydroponics vs Large Commercial Hydroponics

Q.  Can I grow peppers vertically – like I do my tomatoes?  How do you do it?
A.  Some information from the University of Florida Extension division at is fascinating – if you are interested in doing “The Poor Man’s Hydroponic Method” of growing peppers vertically.  Pictures of the two common commercial growing methods – the Dutch V and Spanish methods are posted at  Key paragraphs from the article are duplicated at the bottom of this article.
The Dutch V method prunes the plant to two main branches, and then guides those up strings in a V shape.  Little pruning is done in the Spanish system of growing.  Pruning to two or four main branches is common practice, and thereafter no pruning is done.  Vertical support is provided by poles and strings, or by large tomato cages. 
When a pepper plant is carrying the maximum weight of peppers the plant can support, it will stop flowering and fruiting even though there may be weeks or even months left in the growing season.  Removing green fruits as soon as they mature signals the plant to continue flowering and setting fruit, and the result is fruit being set throughout the growing season, and obviously more fruit per plant.

“Greenhouse pepper cultivars generally have an indeterminate pattern of growth. Because the plants can grow up to 6-ft tall during a growing season of 250 days, they need to be supported vertically. Pepper plants can be trellised to the Dutch “V” system or to the “Spanish” system ( Fig. 8 ).

“Trellising plants with the “V” system consists of forming a plant with two main stems by removing one of the two shoots developed on each node and leaving one or more adjacent leaves per node. The pairs of stems are kept vertically by the use of hanging twines that are wound around the stems as they grow. The “V” trellis system is used by Dutch and Canadian growers.

“Some of the commonly used cultivars are Parker, Triple 4, Cubico, and Lorca for red; Kelvin, for yellow; and Neibla, and Emily, for orange fruits. New pepper cultivars for greenhouse production are introduced every year by seed companies

“When comparing cultivars for those with the highest yield and fruit quality characteristics with low amounts of culls or other disorders, the best red cultivars were Lorca, Torkal, Triple 4, and Zambra; yellow cultivars were Pekin, Kelvin, Neibla, Bossanova, and Taranto; and orange cultivars were Paramo, Lion, and Boogie
“Greenhouse pepper crops in Florida are grown in soil-less culture. Thus methyl bromide is not needed, yet problems with soil borne diseases, and insect and nematode pests are avoided. The plants are grown in containers filled with soil-less media such as perlite, pine bark, or peat mixes. The media can be reused for several crops (two to three) if disease contamination does not occur
“Pepper plants in soil-less culture are fertigated (watered and fed) frequently with a complete nutrient solution. Nutrient solution concentrations are similar to those used for tomatoes grown in soil-less culture. In plants at full production, the nutrient concentration levels can reach N: 160, P: 50, K: 200, Ca: 190, Mg: 48, and S: 65 ppm, respectively. The irrigation solution also provides the plants with micronutrients.
“The pH of the irrigation solution is maintained at values between 5.5 and 6.5, and the EC, depending on the nutrients concentration levels, will have values between 1.5 and 2.5 mS per cm.”

T-Frames in 4′-Wide Grow-Boxes

Q(s).  I have questions on building the T frames.   I read in one of your earlier posts that when you have a 4′ x 30′ box you place the 4×4 posts on the inside of the box but at the outside edges.  Is that correct?
1. So I would use 8 posts ( four on each side) on each bed?
2. Why have 16″ or half of the T hanging over my grow box into the 3.5′ isle?
3. Why not just use 4 posts placed in the center of the two foot-wide bare spot in the middle of the four foot bed.  The end of the T”s would be 16″ narrower than the bed or 8″ short from the edge on each side.  Would it hurt to have the plants climbing up on an angle from the outside of the box towards the center 8″?

4. I may try the PVC frame over the T-frames to make a greenhouse, in order to extend the growing season.  Is that a good idea?

If I try enclosing the bed is this the reason for placing the T posts on the edges of the box?  Then would I walk down the 2′ isle in the middle of the 4′ bed?

5. How much Pre-Plant Mix do I spread on the inside of the grow-box before I fill it with my mixture of sawdust & sand?  The Gardening Course says 2 lbs. For a 18″ X 30′ bed.  Do I double that and put 4 lbs. Down and not put any gypsum down in the center of the box?  The Grow Box Garden book said 10 pounds of gypsum for a 5′ X 30′ box?


1.  Yes, if you are using a 4′-wide box, one big reason for doing so is to maximize your yield in a given space.  You can put two rows of climbing plants in a 4′ bed, which produces as much in 7.5′ width as an 18″ box or bed grows in 10′ of width.  But you should expect to be diligent in your pruning!
2.  The T hangs out into the aisle only 12″ or 13″.  This maximizes the sun-exposure for your plants and uses the space most efficiently.
3.  Have you ever seen poles placed like an indian tepee, with plants placed around the outside, and trained to climb the tepee?  That’s a similar idea, and it is just the opposite of what you want.  As the plants grow taller and bigger they need more light, but because they are growing toward each other and getting closer and closer together, they get less and less light, thus greatly reducing your yield.  If you place your T-Frames in the middle of the Grow-Box, in order for them to get adequate light, you can only grow 1/2 as many plants in the same space.
4.  A PVC frame over the top, such as the one shown in the picture in the Photos section of the, is a very good idea.  You can then use your Grow-Box as a greenhouse in the spring, and it will extend your harvest by several weeks in the fall.  I recommend you take the plastic off, however, in the summer, as it provides some shade, and you want maximum sun (unless you are in the tropics and the temperatures are over 100 degrees fahrenheit).
If you are using the Grow-Box as a greenhouse in the early spring, you may want to keep it tightly enclosed and walk down the center, but you should ONLY do it after placing 2″ X 12″ boards the length of the box and supported, so you don’t compress the soil mix.  After your plants are growing, and especially when they have begun to mature, you should not walk down the center of your Grow-Box.  And there will be no room for you to do so, even if you wanted to. 
In building the frame and covering it with plastic, you should nail 1″ X 2″ boards to both sides of the plastic at the bottom, on the sides of the Grow-Box.  String ropes under 4 points along the side, and tie loops in the ropes.  Then raise the sides by hooking the loops to a stratgeically-placed nail for maximum light on warm days, and so that you can get into the box to feed and harvest.
5.  Since Grow-Box Gardens was written 30 years ago, Dr. Mittleider has determined that 5# of Pre-Plant mix is adequate to be placed on the dirt under a 5′ X 30′ box.  For your 4′-wide box spread 4# of Pre-Plant Mix evenly on the soil under the box.  Of course you will also mix 4# of Pre-Plant,along with 2# of Weekly Feed into the soil mixture as you are filling the box.

Germinating Tomatoes In The Greenhouse

Q.  I have had trouble getting my tomatoes to germinate in the greenhouse.  Is there a variety that you would suggest? I live at 41 degrees North latitude and 5,000 feet elevation. Any additional advice would be appreciated.

A.  Tomatoes need a constant sustained temperature in the 70’s for good germination. Get a good thermometer, then insulate your greenhouse as much as possible, without losing light. Heating the entire greenhouse is too expensive, enclose the table where your plants are growing in clear plastic and heat only that space, thus creating a greenhouse within a greenhouse.  We use heaters this time of year, either propane, kerosene, or electric in order to sustain good growing temperatures for tomatoes and other warm-weather plants.

Grow 100 Tons of Tomatoes On 1 Acre

Q.  I’ve heard the Mittleider Method can produce 100 tons of tomatoes on one acre.  How is this possible, since field-grown tomato growers do well to produce 35 tons per acre!

A.  I’ll describe “The poor man’s hydroponic method” of growing in a 1-acre garden, using raised beds, or Grow-Boxes, as Dr. Jacob R. Mittleider calls them. And remember that just one acre of tomatoes grown successfully using this method – and selling them for just $.50 per pound, would yield $100,000 per year!

One acre (43,560 square feet) will accommodate 312 – 30′ rows of tomatoes, grown in 4′ X 30′ Grow-Boxes, with 3 1/2′ side aisles, 5′ end aisles, and 5′ aisles around the perimeter.

Planted 9″ apart, that amounts to 12,792 tomato plants (41 per bed).Growing a large tomato that averages 8 ounces (some varieties actually average 10-12 ounces), feeding and watering properly, and growing vertically, each plant should produce 16# of fruit from July through October in Utah.

A good variety will produce a “hand” of 3-7 tomatoes every 5-7″ up a 7′ stem in 4 months’ production. Using 4 per hand X 12 hands X 1/2# per tomato = 24. And I will reduce that by 33%, in order to be very conservative.This amounts to 204,672 pounds of tomatoes – or $102,336 at $.50 per pound. Who said you couldn’t live off the land!

There certainly are costs – as there are to any business. 1) Creating and filling the boxes, 2) making T-Frames, 3) wires or pipes – and baling twine strings, and 4) automating the watering are the major costs, but these are one-time capital expenditures, and will be more than recovered in the first year.

Now, suppose you’d like to increase your yield (remember, I’ve said hydroponic growers can grow 330 tons or 660,000# per year on one acre.  Of course, they have huge investments in year-round greenhouses, etc., etc.).  By simply putting an arched PVC roof over each pair of your Grow-Boxes, and covering them with 6 mil greenhouse plastic, you can lengthen your growing season by two months, or 50%!

Now you’re looking at over 300,000# of tomatoes per acre, and more than half the yield of the expensive hydroponic growers – but you’re growing “in the dirt”, because your boxes are open at the bottom, so your plants get all the natural nutrients available to them from the soil.

And you don’t need the greenhouse covering all the time, so your plants can benefit from direct sunlight as well.Imagine That!  And your garden can qualify as an organic garden, if you do everything properly, and don’t use any pesticides or herbicides.

Do you think these numbers are hard to believe? Just visit a greenhouse tomato operation and see tomato plants that are 20′ and 30′ long – still producing after more than a year!

Several of Dr. Mittleider’s books teach tomato production, and I encourage you to read them.  Go to

Pictures of the 320 plants I’m growing on 1200 square feet adjacent to Utah’s Hogle Zoo, in Salt Lake City are posted at

Growing Commercially – Mittleider VS Hydroponics

Q.  We want to go into gardening commercially, and hydroponic greenhouse growing has been recommended.  How is your Method similar or better for us than going hydroponic?

A.  Before you spend any money on Hydroponic buildings and equipment you need to learn about the Mittleider Method, for sure! Building a Mittleider-style greenhouse will save you many thousands of dollars in the building of it and many thousands more in operating costs.  The Mittleider Method is sometimes referred to as modified hydroponics, because we feed the plants the 13 necessary nutrients, in a scientifically balanced ratio.  However, rather than putting expensive instantly water-soluble formulas in the water supply, we use Natural Mineral Nutrients that are easily and inexpensively obtained and apply the nutrients right on the soil – then water them in.  Also, as alluded to in the previous paragraph, unlike hydroponics, we grow plants right in the ground, or if we’re in Greenhouses we use raised Grow-Boxes with open bottoms, so the plants still have access to the natural soil – to obtain other nutrients they may want or need.  Mittleider gardens are well known for producing tremendous yields, even approaching those of hydroponics, while our crops like tomatoes are better tasting and cost a small fraction of those grown by hydroponic methods.

Where can I find Advanced topics covered?

When you get ready to think of maximizing your production by growing your own seedlings, using a cold frame/hot house or building your own greenhouse, or growing plants vertically (as I do to achieve over 10,000 pounds of tomatoes on 1/22nd of an acre), consider the Mittleider Gardening Course, which includes what you see on the internet and about a dozen “advanced” topics, and is the student manual for any classes taught by the Food For Everyone Foundation.