Tucson’s cool growing season begins in October and ends in April. It is a period with mild, short days and half the year’s rainfall. Gourmet greens thrive in this season and tolerate the occasional frosts that kill other crops like tomatoes and peppers. Other crops for this season include cabbage relatives like broccoli, cauliflower and Asian greens, plus root crops like beets, radishes, and carrots. Herbs like cilantro, parsley and chervil are also cool weather plants. An easy way to enjoy growing and eating gourmet greens is with container gardens. While space (or lack of it) is an obvious reason to try container gardening, it is not the only reason. They can be conveniently located close to where they’re used, don’t require much time to create or maintain, are inexpensive, and can be planted into works of art!

Plants need sunlight, water, oxygen, soil, and nutrients to live.
All these elements need to be available to greens in optimum amounts for good production.

Sunlight
There is no shortage of sunlight in Tucson even in winter. Gourmet greens and other crops will thrive in full sun but even tolerate filtered shade like that cast by deciduous trees.

Water
Water needs vary with weather, the kinds of plants and their growth stage, soil type, and other factors. Keeping the soil moist, but not wet, is best for greens and other vegetables. This might require watering twice daily in October, but only twice weekly in January. Check by using your finger to feel a half inch down in the soil. If it is dry that far down, it is time to water. If it is still moist, wait. Overwatering is as bad as underwatering and can lead to root rots and poor growth.

Oxygen
Plants need oxygen in their root zones to live. Having loose, well drained soil is the way to ensure this. Cultivating the soil surface occasionally will improve water and oxygen infiltration too.

Soil and Nutrients
Soil mixes for container gardens should be free of disease and weed seeds, should hold moisture and nutrients, drain well and be lightweight. Some growers use “soil-less” mixes for growing container gardens, but they dry too quickly here and are difficult to re-wet. An ideal container medium for Tucson needs to hold water more than in wetter climates. A good recipe is:
1 part pumice
1 part sand
1 part loam soil
3 parts compost

Even with a good mix, container gardens can suffer from low fertility because frequent watering flushes nutrients out. For every cubic foot of the soil mix, add 1/4 cup each of rock phosphate, mineral sulfur, and dried chicken manure. These amendments are long-lasting and will help maintain plant growth and productivity. Also add a low-strength fertilizer like fish emulsion liquid according to the manufacturer’s recommendations: more about that below.

Greens may be purchased as transplants from local nurseries or can be grown at home. Starting seeds is easy, inexpensive, and allows for greater choice of varieties. Seeds should be started in a sunny, warm area 4 to 8 weeks prior to transplanting into containers. Mid-September is ideal in Tucson. Use seed trays with 2 to 3 inch wide compartments. These trays are available at most nurseries and large hardware stores. Fill the trays with a good soil mix like the one described above after sifting out any large materials. Cover the seeds to a depth of 1/4 inch or less (most greens need to be very near the surface to germinate) and keep the surface evenly moist until the seedlings are well germinated and growing. Transplant when they are 3 to 4 inches tall and be careful to avoid injuring the young root systems.

Containers of greens can be attractive as well as tasty.
Tips for planting attractive combinations include:
Use several varieties for pleasing combinations of color and texture. Combine varieties that have similar cultural requirements. Include tall plants, short plants, and ones that will grow over the edges of the container. Plant a bit tight for a lush, full effect, but compensate with extra fertilizer and water.Care of Container Gardens

Pay close attention to watering container gardens. The volume of soil is relatively small, so containers can dry out quickly, especially if they are on a concrete patio in full sunlight. Clay pots dry faster than non-porous kinds because moisture evaporates from the sides . Dark pots heat up more and dry faster than light colored ones. Check containers at least once a day on hot, dry, or windy days.

The easiest way to add nutrients to container gardens is with water-soluble fertilizers. Fish emulsion or compost tea will boost plant growth without the danger of burning. But don’t get fish fertilizer on the leaves--it will make everything taste of anchovy! Do not add more than the recommended rate of any fertilizer. Doing so can burn and kill your plants. If sowing seeds, wait to fertilize until after the seeds have germinated and are showing true leaves. If you use transplants, begin watering with nutrient solution the day you set them out.

Thinning plants is difficult because it means killing baby greens. Just remember that the ones that are left will have more room to grow and will be healthier and more productive. Begin thinning when the plants have one or two true leaves. Weeding will be necessary but make sure you know what seedlings of your planted greens look like before ripping out any small plants!

Salad greens provide tasty eating for insects as well as humans so plants should be inspected often. Small green caterpillars are the most common pest on greens and are easily controlled with a powder or liquid form of Bacillus thuringiensis (Bt). Bt is is a bacterium that is harmless to humans but toxic to many kinds of leaf eating caterpillars.

Other insect pests include aphids, cutworms, borers and beetles. They are controllable with minimal effort or can be tolerated. Put in a few extra plants for the bugs and don’t hurry to get rid of them all; “good” bugs will be attracted to, and eat, the “bad” ones. The following practices will keep most bugs to a tolerable level.

Since you cannot avoid all insect damage, plant more of a crop for an adequate harvest. Check plants often and hand pick any insects before they become too numerous. Encourage natural insect predators when possible. Do not plant crops in large blocks. Mixing different types of plants helps slow the spread of insects. Supplement mechanical (pickin’ and squishin’) controls with biological and natural pesticides. Fertilize, cultivate and water to promote vigorous growth. Healthy plants seem less attractive to insects, and those that are attacked can survive and still produce a crop. Use transplants when possible--they develop more quickly than seeds and the quicker you can grow and harvest the greens, the less chance of insect pests seriously damaging them. Remove garden debris or nearby weeds that might serve as breeding or hiding places for insects.

Tucson’s low humidity keeps many diseases at bay. In wet, cold winters, however, fungal diseases can kill crowded plants or cause other problems. The following are practices that help to control plant diseases: Use disease-resistant varieties whenever they are available, as well as varieties suited to the local growing conditions. Provide good soil, good drainage, and adequate sunlight. Improve the soil with organic matter and fertilizers to develop the best soil tilth for growing seeds and plants. Use disease-free transplants and seeds from reputable suppliers. Eliminate weeds around the garden area that might harbor diseases. Control insect pests that serve as disease carriers. Do not overcrowd plants. It prevents good air movement and exposure to adequate sunlight. High humidity and too much shade caused by these conditions increases the development of some diseases.

Keeping records for your garden is essential. A garden journal is easy, fun and indispensable way you can record the weather, successes and failures, random thoughts, and ideas for improving the garden. Make a sketch of your newly planted gardens. It can help when you wonder, six weeks later, what you planted where!

There are three methods for harvesting greens:
1) Cutting entire mature heads or plants
2) Cutting plants just above the base and
letting them resprout (“cut and come again”)
3) Selective harvesting of leaves.

Number 1 is best if you want to grow and harvest large heads of lettuce or other greens and use them at once. Number 2 allows large heads to develop but leaves the root and stem material for regrowth of new (though usually smaller) heads. Number 3 prevents large heads forming, but is a good way to harvest only what’s needed and the plants last a long time.

It is always better to pick and eat greens immediately, but most
gourmet greens will last a week or more in the refrigerator in plastic
bags. Pick them carefully and put in a bag but don’t wash them until
you’re ready to eat them. Washing damages the leaves and the moisture makes them prone to rot.