The Urban Farmer: Climate, temperature, humidity & automation

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The Urban Farmer, Issue #041 *  Ventilation, Humidity, Temperature & Automation

“Gardening requires lots of water – most of it in the form of perspiration.”   ~Lou Erickson

Ventilation: a breath of fresh air

How important is airflow to a hydroponics garden?

Air flow is arguably one of the most important aspects of a grow room or greenhouse. Not only does it deter mold and fungi from developing, but it also provides much-needed CO2 for the plant’s overall growth and development.

A well-ventilated room will yield more than a room with no ventilation. The only time this is not the case is if the room is controlled with a complete climate control system. In such a room, air-conditioners and a CO2 injection system are essential.

CO2 is then introduced not by airflow but through a designated injection system. It is important to note that CO2 injection works best in a completely controlled climate. To understand why ventilation is important consider the goal of setting up a greenhouse or grow room. The aim is to mimic the outside environment in a controlled and therefore higher yielding area.

Are oscillating fans needed?

An oscillating fan is necessary for adequate air movement in the room itself. It helps to move warm air in winter and cool air in summer evenly through the plant canopy. Oscillating fans help maintain consistent room temperatures

How important is Humidity & Temperature?

It is extremely important to monitor & control relative humidity around a hydroponic crop. Relative humidity should be in the range of 50-70% and temperature should be around 70-80 degrees F. during the day and 65-72 degrees at night. Extremes in temperature should be avoided. Temperatures above 90 degrees stop plant development.

High humidity increases the risk of molds and mildew developing as well as encouraging an irresistible habitat for pests like spider mite & sciarid fly. High humidity also reduces transpiration, which in turn reduces circulation in the plant of essential elements like calcium.

Low humidity, or dry air, can decrease the likelihood of fungal diseases but it also increases transpiration in the plants which can in turn dry the leaves and growing points out excessively.

This can produce a lack of pollination in tomato crops because the growing point dies. This of course affects the overall harvest of the crop. Increased transpiration in the leaves also affects the fruit already on the plant. Fruit can die or flowers rot because less water is being channeled to the fruit/flower.

A Cadillac Garden: Climate controller

If you have an enclosed grow room or a greenhouse, you have the option of automating your garden to strive for the “perfect environment”.

Basic Garden Climate Controller

The cheapest and most basic garden climate controller usually controls only temperature and humidity and runs your exhaust fans when needed. For a small additional charge, CO2 controls can be added to most basic models.

This allows you to coordinate all of your environmental controls in one place without spending hundreds of dollars on a controller that is more sophisticated than you need. Most home indoor gardens can be handled effectively with just the basic climate controller.

Complete Garden Climate Controller

If you have a more complex hydroponic garden setup or need a fully-automated system, you can purchase a complete garden climate controller.

These are especially useful if for people who travel frequently and cannot maintain their garden regularly. They typically include a timer with several outlets to control different banks of grow lights, along with outlets and thermostat controls for your exhaust fans or dehumidifiers.

Water pumps are activated by a timer and many climate controllers include a photosensor, allowing you to conserve energy by running your pumps only when the grow lights are off.

Another advantage worth the extra expense of a complete garden climate controller is the control it gives you over your CO2 system. Most controllers allow you to coordinate the infusion of carbon dioxide with the exhaust fans to cut down on wasted CO2.

Hydro Tip of the Month

One of the best things about hydroponics is its versatility and adaptability. Your choices for this gardening method are wide open. You can grow some heirloom tomatoes in a 5-gallon “bucket bubbler”, gourmet hydro herbs on a kitchen windowsill, or sugar baby melons in a large bedroom farm. You can create a garden from 2-liter soda bottles and hang it on your patio fence. Or you could spend thousands on a state-of-the-art NFT or aeroponics system. Get started on your decision here:

We hope you have enjoyed this issue of The Urban Farmer Ezine. Each month, we will bring you another inspiring photo, gardening quote, or idea, plus fresh new hydroponics news, techniques & products.