Urban orchards: Introduction

The urban garden is a great way to grow your own vegetables if you live in the city. Urban gardens began to become popular in World War II, producing up to 40% of plant-based foods in U.S. cities. Growing our own vegetables knowing what we are consuming and how it has been produced is highly valued today. It is also an exciting, de-stressing and educational hobby for the little ones. They have been fundamental and are fundamental during difficult times when food is scarce, in fact, the UN Conference on Trade and Development, made it clear that the way to move towards the eradication of hunger in the world is to move from an industrial agriculture to a model based on rural development and the prominence of organic and local agriculture.

An urban garden is comparable to an orchard in the garden; these are covered spaces or not for the cultivation of vegetables and fruits on a domestic scale. The quality of the products obtained in our garden is equal to and even superior to that of the products that we can acquire in greengrocers and large surfaces.

Vegetables are of great importance for the food and good nutrition of our family, their leaves, fruits, roots, stems and flowers are consumed to meet the needs of our body, for their high content of minerals, vitamins and proteins that contribute to improve and maintain good health. We are going to focus on a group of vegetables that are easy to grow in pots or terrariums.

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Seedbed.

The first thing we must solve is how to stock up on plants for our garden. Unlike what happens with ornamentals that there are nurseries and online stores that sell you the plant directly, in the Spanish southeast there are horticultural nurseries (they are known as SEEDBEDS) but their business is not to sell retail. Certain ornamental plant nurseries are supplied with some horticultural trays at certain times of the year (early spring and early autumn) but if we want to ensure a continuous supply of plant we must have our own seedbed and for that there is a wide assortment of seeds of all kinds and variety of vegetables on the market.

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With our own seedbed we will plan to have fresh vegetables all year round; we will only need a few trays of seedbed and substrate.

The management of the seedbed climate is decisive for an optimal development of our plants and is also the main tool of defense against pests and diseases. The optimum temperature is between 20-25ºC and 60-70% relative humidity. My advice is that whoever can and has a room, attic, garage, etc., in which he can put, for example, a lighting equipment of 600 watt sodium bulbs ensures a germination and growth of the plant in a constant period of time throughout the year; the cycle of plants is shortened by long, warm days and lengthens in winter. I show you the equipment I have in a wooden shed.

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If you do not have space there are electric seedbeds on the market that control temperature, humidity and ventilation; the only thing they do not provide is the lighting then we must place them where they receive light.

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A third more system of walking around the house to recreate the ideal germination conditions is to cover the seedbed tray with transparent plastic film, making some holes in the film to ensure gas exchange.

There are several types of seedbed trays with different number and size of alveolus; the smaller the number of alveoli, the longer the plant can be in the seedbed, resulting in a larger plant.

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We will prepare our substrate for seedbed that can be perfectly 60% blonde peat or coconut fiber, 20% worm humus and 20% perlite. The first step will be to fill the alveoli of the tray with the substrate leaving it half a centimeter below the edge so that the water does not drain. We will carry out a pre-irrigation of planting until saturating the substrate and we will let it drain. We will make a hole with a stick and put the seed to a depth of between a quarter of a centimeter to half a centimeter (larger seeds deeper and vice versa) and fill the hole with substrate and moisten with a sprayer. If we have done everything right the plants should germinate in 5-7 days. To avoid nascence failures we will put two seeds in each alveolus and if the two seedlings come out we will eliminate the weakest one.

At first we must water with a sprayer to avoid dragging of substrate and consequently seeds. We will not let the surface of the substrate dry.

We will not start fertilizing until 10-12 days after germination and we will do it with a complete solution poor in nitrogen and rich in phosphorus. At first the plant will be nourished by the reserves of cotyledons.

As this is a very delicate phase for plants we will make sure to:

In summer water in the morning or afternoon and in winter at noon. With this we get that the temperature of the water does not damage the root.
The electrical conductivity shall not exceed 1.8 dS/m in the fertigation solution.
The pH of the fertigation solution shall be between 5.5-6.5.
Provide the right light; an excess of light in this phase can be fatal for the seedlings.

Transplantation.

Depending on the conditions in which our seedbed has developed, the plants have to be ready for transplantation in 25-35 days (depending on species we will transplant when they have emitted the 3rd or 4th leaf without counting the cotyledons).

Transplantation is a stressful situation since in nature it never happens that someone or something takes a plant out of one location to place it in another; it is an action against nature. To minimize the negative effects on the plant we will follow the following indications: a week before transplanting we will reduce the water supply to the plant so that it suffers a loss of moisture and hardens its tissues; with this we get them to be more resistant to the conditions of their new living environment. A seedling with a lot of moisture has very watery and poorly developed roots, while one that had a water deficit has more developed roots having had to work harder to get the water. At the same time that we decrease the water we will change the fertilizer to a nutrient solution poor in nitrogen and rich in phosphorus. When the plants begin to be ready for transplantation, one or two weeks before they should be removed from their growth site and take the trays, gradually, to places increasingly similar to the final transplant site; for example, going from shade to semi-sun, until reaching the direct sun before transplantation. Once acclimatized, transplantation can be performed.

As for the container, I recommend pots of 5 to 10 liters for tomato, cucumber, pepper, eggplant and similar plants, and for lettuce and radishes trays that already exist in the market to which we will make some holes to guarantee drainage if they do not have them.

We will fill the trays with substrate and saturate with a balanced fertigation solution of macros and micros, with an N/K ratio of 1.7-2. We will let drain. Two or three hours before transplanting we will water the seedbed tray to make it easier to remove the plant and remove the plant from the alveolus of the tray with care not to break it; if we find resistance we can help ourselves with a small knife or a spoon to pry the root ball on one side. Make a hole equal to the volume of the root ball and introduce the plant into the new substrate.

The transplant operation is best done first thing in the morning or late afternoon with good weather, and mid-morning in winter, to avoid damage from heat or cold.

Once the transplanted plants will be placed in a semi-shaded site and protected from the wind until they take root in the new substrate. We will keep the substrate moist, but not waterlogged.