TEN POINTS:  A way to successful 4-season crops, 4-season harvest.

 1.  Select appropriate crops for the harvest season you are planning for.  Succession planting is the key for each season.

 2.  Keep it simple – if something doesn’t work the first time, try again in the next round of planting (2 weeks later) , then reassess – ‘is this crop worth a struggle?’

 3.  If pests seem to be in charge, get rid of the plants that are their hosts if the critters are persistent in spite of your efforts to chase them away.  It’s simplest not to fight the ‘forces of nature’ --why get discouraged? 

 4.  Crop protection includes protection from excessive heat, excessive moisture and excessive cold. 

 5.  Modulation of temperature extremes in summer and winter is crucial for happy plants and abundant growing.

 6.  Decide and define your acceptable limits for technological intervention to enhance growth:  e.g. supplemental cooling in summer, supplemental heating in winter.  These measures can be costly, depending on your growing system.

 7.  Feed the soil, the plants feed themselves!

 8.  Cleanliness is important when crops are growing year-round, whether outside or inside:  e.g.   regular removal of dead and infected plant material.  

 9.  If it’s a crop you like- try it again another year, regardless of success or failure!  (Rotate locations.)

10. Keep it flowing and have fun!


1.  Appropriate crops for the season- freshness, variety, quality

In four season harvesting, the important factors that determine the appropriate crops for each season in a given location are mainly temperature and daylength (i.e., the amount of sunlight every day to support growth).  Pioneers in the early efforts in 4 season growing, like Eliot Coleman in Maine, traveled around the world at specific latitudes to discover what crops grew best at given latitudes. (South San Isidro is at 35 degrees, 27”).  Daylength is the overriding determining factor for what plants grow at any given latitude, even more than temperature.  Many veggies will grow in sub-freezing temperatures as long as they have adequate sunlight. For these plants, protection compensates for colder temperatures and wind.  For most typical cool season crops, our winter daylength is adequate for development to harvest if the seedlings have a chance to ‘take off’ in around 7-8 hours of good light.  If the seedlings for root crops like beets are started when temps are low and light is short, the roots will require lots of time for development, perhaps as much as 4 months. In the case of beets, in the meantime some greens can be harvested.

In the high desert, let’s say 7000 to 10,000 feet, our frost dates are October 15 (Nov 1 for Santa   Fe) and May 15 – the dates for first and last frost.  The greatest daily extremes in temperature occur between these dates.  Outside temperatures on a typical (not extreme) given day in mountainous areas can range from 32 degrees (or lower) to around 60 degrees (30 – 40 degree range, more or less).  Inside a greenhouse, the daily temperatures may range from 35 degrees to 85 degrees (40 – 50 degree range, more or less).  On the coldest days of sub zero weather for several successive nights, the lowest temperatures we saw in the green house were 27 degrees one time, 29 degrees a couple of times, and a few nights of 31 degrees. (Remember, what is really extended in this 4 season process is the harvest season, not the growing season.)    

To what extent the temperature extremes are problematic depends on the specific crop.  In preparing for cool season crops for the winter, start planting early, around August 1, so that there are plenty of seedlings that have adequate light and warmth to develop before the cool end of the temperature range is too low.  Turnips and mustard greens are examples of two crops that seem to be not so sensitive– they do well under many conditions. Kale is pretty easy as well. In contrast, in my experience, radicchio, for example, doesn’t start well when the low end is too low or the high end too high. Spinach will bolt, especially indoors, with a high end much over 70 degrees.

Plant repeatedly every two weeks for an extended harvest- its easier to have extra seedlings to remove or transplant than not to have plenty started.  Depending on temperatures for a particular year, seedlings started after the end of September may or may not take off.  Germination may be erratic, at best. 

Remember to rotate the planting locations among different crops

Some popular crops to start in August

broccoli                                                                      spinach

kale                                                                           radicchio

chard                                                                         corn salad     

cauliflower and other brassicas                                     mustard greens

lettuce – several varieties                                            arugula

green beans                                                               endive

radishes                                                                     peas

carrots                                                                       turnips



Popular warm-season crops to start indoors in February through April:

lettuce  ( late winter, early spring)

peas                      “

spinach                  “

chard                    “



Start March -May:



squash  - all varieties

peppers, chilis



2.  Keep it simple

The challenging combination of factors in the high desert, including large daily temperature ranges, unpredictable onset of cold or an erratic cold night, and even an extended very warm ‘Indian summer’ can really be confusing to some seedlings.. see what works for your growing situation, try planting  a couple of times, then move on if the seedlings just don’t keep going or if they bolt when very young.…


3.  Persistent pests

It’s awfully frustrating to feel that you have won the battle against a nasty little pest, like aphids, on one plant type, only to find a few weeks later that the little guys have moved on to another… its best to remove the infested plants rather that risk a major epidemic – particularly if you are growing organically!


4/5  Plant protection, modulation of extremes

In sustained succession planting, protection involves simple measures to help plants adapt to new and shifting conditions… like cool season crops shifting from warmer weather when planted to cooler conditions for growing.  So, in the early sowings for cool season crops, veggies such as lettuce, kale, broccoli, chard etc may require a little shade cloth to cool down the end-of summer hot sun, especially mid-day and late afternoon from the west.  Protection from excessive cool may involve use of cold frames – portable if outdoors- in deep winter. In the greenhouse, if you have some willing warm-season veggies (e.g. tomatoes) growing in the winter, on the coldest nights they may like a piece of remay or shade cloth tossed over them.  Also, these plants will do best if in the center of the greenhouse, away from the frosty sides…

Any greenhouse system can benefit from a thermal mass created from a water tank (or hot tub!) to modulate temperature extremes.  If large enough, and depending on the structure, the benefit may be as much as a 10 degree difference that is maintained between indoor and ambient outdoor temperatures, with the day-night extremes somewhat leveled.  The cost of adding a heater (800 watt s?) to a large tank of  500 -1000 gallons will be considerably less than heating the greenhouse (though the overall impact is less direct, for sure) .

In addition, during winter both outdoors and indoors, the soil itself serves as a thermal mass by storing the warmth of the sun. 

The issue of excess moisture may be greatest in a greenhouse situation. Excess moisture contributes to risk of disease, especially fungal diseases.  There is a fine balance between adequate water in the summer to accommodate the plants in the heat of the greenhouse, versus too much water which brings on fungal diseases such as blossom end rot in the humid environment.  In the winter, the problem of excess water in the soil can lead to various types of root rot.  However, in the winter, a moist soil helps the plants to sustain a cold snap.  It’s very challenging to clean up soil contaminated with fungal spores. 

6.  Technical intervention

Your particular needs or goals may determine the extent of technical intervention you choose to use, be it heating, cooling or thermal mass.  Thermal mass is the least expensive in the long run, but is less capable of fast quick -fix response than heating or cooling…  Solar-run equipment is a great choice as an alternative, such as solar-operated fans or fountains. In my experience, in our climate, either no or minimum technical intervention is required to have lovely fresh greens and veggies year-round.  Solar –run fans seem to be particularly useful year-round to move the air and reduce fungal attack, to circulate warm air in the winter and cool air in the summer to help equilibrate the temperature. 

7.  Feed the soil

A good rule of thumb is to feed the soil- compost and other organic amendments, are all beneficial both inside and outside… A good living soil nourishes plants and helps discourage pest problems.


8.  Cleanliness

In any intensive growing situation, sanitation and cleanliness are of utmost importance.  Remove all dead or diseased vegetation, including  entire plants if need be.  When plants are dense, make sure to look underneath for rotting leaves and stems.  This practice will help to ensure healthy, disease-free soil.  Beneficial insects can be used to assist in cleaning up undesirable insect pests. 

Exposing soil to a good freeze is one way to help kill off pathogens.  This is a natural process for soil outdoors,  and may be helpful – though radical! -  in a greenhouse if it’s possible to remove sensitive plants and then open up and allow the temperature to drop for several nights.


9.  Rotate your crops

For sustainable growing, rotate your crops so that successive plantings in the same space are plants from different families.  This practice  will reduce problems with pests and sustain healthy soil


ENJOY the bountiful harvest year–round!