Soil Containers

shapes and sizes and can be constructed of almost anything-clay, metal, plastic, wood, and wood fiber are the most common. Cannabis will grow in any clean container that has not been used for petroleum products or deadly chemicals. Clay fiber and wood containers breathe better than plastic or metal pots. Heavy clay pots are brittle and absorb moisture from the soil inside, causing the soil to dry out quickly. Metal pots are also impractical for grow rooms because they oxidize (rust) and can bleed off harmful elements and compounds. Wood, although somewhat expensive, makes some of the best containers, especially large raised beds and planters on wheels. Plastic containers. are inexpensive, durable, and offer the best value to indoor growers.

Rigid plastic pots are the most commonly used containers in grow rooms. Crowing in inexpensive, readily available containers is brilliant because they allow each plant to be cared for individually. You can control each plant's specific water and nutrient regimen. Individual potted plants can also be moved. Turn pots every few days, so plants receive even lighting and foliage will grow evenly. Huddle small, containerized plants tightly together under the brightest area below the HID lamp, and move them further apart as they grow. Set small plants up on blocks to move them closer to the HID. Individual plants are easily quarantined or

Marijuana Soil Containers
White pots refJect light and heat. Black pots set inside the while pots keep roots in a dark environment
Grow bags are economical, lightweight, and reusable.
Good Potting Soil Marijuana
The potting soil bag can also be used as a container.


: The Indoor/Outdoor ME

Woven coco fiber pots from General Hydroponics breathe well, do not compact, can be used several times, and arc biodegradable.

Containers on casters are easy to mow? and stay warmer when up off the floor.

Containers must be: Clean

Have adequate drainage holes Big enough to accommodate plant dipped in a medicinal solution. Weak, sick, and problem plants are easy to cull from the garden.

Grow bags are one of my favorite containers. Inexpensive, long-lasting grow bags take up little space and are lightweight. A box of 100 3-gallon (13 L) bags weighs less than 5 pounds (2,3 kg) and measures less than a foot square. One hundred 3-gallon (13 L) grow bags can be stored in two 3-gallon (13 L) bags. Imagine storing 100 rigid pots in the same space!

Grow bags are very easy to wash and reuse. Empty out the soilless mix and submerge bags in a big container of soapy water overnight. Wash each one by hand the next day and fill with soil. I like them much better than rigid pots because they are so practical.

The potting soil sack can be used as a container. The moist soil inside the bag holds its shape well, and the bags expand and contract with the soil, lessening the chance of burned root tips that grow down the side of pots.

Fiber and paper-pulp pots are popular with growers who move their plants outdoors. The bottoms of the pots habitually rot out. Painting the inside of the fiber container with latex paint will keep the bottom from rotting for several crops.

Set large pots on blocks or casters to allow air circulation underneath. The soil stays warmer and maintenance is easier. Planters should be as big as possible but still allow easy access to plants. The roots have more room to grow and

replanting directly in the floor of a basement or building gives roots plenty of space to expand.

■ -■■• nm less container surface for roots to run into and grow down. With large pots, roots are able to intertwine and grow like crazy.

Grow beds can be installed right on the earthen floor of a garage or basement. If drainage is poor, a layer of gravel or a dry well can be made under the bed. Some growers use a jackhammer to remove the concrete floor in a basement to get better drainage. An easier option is to cut a hole in the basement floor and install a dry well. Knocking holes in basement lloors could cause water seepage, where water tables are high. When it rains, the water may collect underneath; the garden seldom needs watering, but plants are kept too wet.

A raised bed with a large soil mass can be built up organically after several crops. To hasten organic activity within the soil, add organic seaweed, manure, and additives. When mixing soil or adding amendments, use the best possible organic components and follow organic principles. There should be good drainage and the soil should be as deep as possible, 12-24 inches (30-60 cm).

At the Cannabis College in Amsterdam, Netherlands, they are growing in large soil beds

Cannabis Raised Beds

You can find this raised bed garden in the grow room at the Cannabis College in Amsterdam,

Install a dry well to evacuate excess runoff.

Marijuana Soil Containers

Flush containers with a mild nutrient solution every month.

Marijuana Soil Containers

Flush containers with three times as much water volume of soil to leach out excess fertilizer salts. Flush containers every month to avoid many problems.

set on a concrete floor. The basement beds are below sea level and filled with outstanding Dutch cannabis. They are able to treat the beds similar to outdoor soil beds, but when watered heavily, water runs out on the floor and it must be mopped up. They also have a problem with ventilation. The ambient climate is naturally humid and the extra water in the large basement increases humidity to above 90 percent, day and night. They employ a large extraction fan and a relatively small intake fan. Air is pulled through the long narrow basement room quickly and efficiently to evacuate moisture and lower the humidity. Even with this much soil, they have to flush individual beds at least once every four weeks to avoid nutrient buildup.

Much heat can be generated by decomposing organic matter, and it warms the room. Ventilation lowers heat and humidity, and helps keep the room free of pests and diseases. An organic garden sounds great, but it is a lot of work to replicate the great outdoors. Most organic growers opt for organic liquid fertilizers and a bagged commercial organic soil mix.

Another drawback to raised beds is that the crop will take a few days longer to mature than if it were grown in containers. But the longer wait is offset by a larger harvest.

Flush containers with a mild nutrient solution every month.


All containers need some form of drainage. Drainage holes allow excess water and nutrient solution to flow freely out the bottom of a container. Drainage holes should let water drain easily, but not be so big that growing medium washes out onto the floor. Containers should have at least two half-inch (1.2 cm) holes per square foot of bottom. Most pots have twice this amount. To slow drainage and keep soil from washing out of the large holes, add a one-inch (3 cm) layer of gravel in the bottom of the pot. Surface tension created by the varying sizes of soil and rock particles cause water to be retained at the bottom of the container. Line pots with newspaper if drainage is too fast or if soil washes out drain holes. This will slow drainage, so be wary!


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Put trays under containers to catch excess water. Leaving water-filled saucers under pots often causes root rot. To avoid water-logging soil and roots, set containers up an inch or two on blocks when using trays,

Nursery trays used for rooting cuttings and growing seedlings must have good drainage throughout the entire bottom. Once clones and seedlings are in place in the tray, the tray should always drain freely with no standing water in the bottom.

Container Shape, Size, and Maintenance

Popular pot shapes include rectangular and cylindrical. Growers prefer taller pots rather than wide, squat containers because the cannabis root system penetrates deeply. Of all the gardens I have visited, squat pots were few and far between. Growers I queried said squat pots may hold more soil for their stature, but they do not produce as extensive a root system.

The volume of a container can easily dictate the size of a plant. Cannabis is an annual; it grows very fast and requires a lot of root space for sustained, vigorous development. Containers should be big enough to allow for a strong root system, but just big enough to contain the root system before harvest. If the container is too small, roots are confined, water and nutrient uptake is limited, and growth slows to a crawl. But if the container is too big, it requires too much expensive growing medium and becomes heavy and awkward to move,

Marijuana roots develop and elongate quickly, growing down and out, away from the main taproot. For example, about midsummer, nurseries have unsold tomato plants that are still in small 4-inch (10 cm) pots and one-gallon (4 L) containers. The stunted plants have blooming flowers and ripe fruit. But few branches extend much beyond the sides of the container; the plants are tall and leggy with curled down leaves and an overall stunted, sickly appearance. These plants are pot- or root-bound. Once a plant deteriorates to this level, it is often easier and more efficient to toss it out and replace it with a healthy one.

Roots soon hit the sides of containers where they grow down and mat up around the bottom. The unnatural environment inside the container often causes a thick layer of roots to grow alongside the container walls and bottom. This portion of the root zone is the most vulnerable to moisture and heat stress and is the most exposed.

Large square pots arc perfect for this hydroponic garden.

Large pots hold a lot of soil and require irrigation less frequently.

This room full of 3-gallon (II L) pots is packed in so tight that you can walk on the pots.

Large pots hold a lot of soil and require irrigation less frequently.

Large square pots arc perfect for this hydroponic garden.

Roots grow quickly and soon encircle (he inside of the container.

Plant age

Container size

0-3 weeks

root cube

2-6 weeks

4-inch pot

6-8 weeks

2-gallon pot

2-3 months

3-gallon pot

3-8 months

5-gallon pot

6-18 months

10-gallon pot

Allow 1 to 1.5 gallons {/1 to 7 L) of soil or

soilless mix for each month the plant will

spend in the container. A 2- to 3-gallon (7.5-

11 L) pot supports a plant for up to three

months, 3- to 6-gallon containers are good

for three to four months of rapid plant


Roots grow quickly and soon encircle (he inside of the container.

Square containers are easy to bunch together when small.

Deep containers are ideal for seedlings that will be planted outdoors.

Soil shrinks when dry; it causes a side the container wall, along-

Soil shrinks when dry; it causes a side the container wall, along-

Surface Breaking Weed
Cultivate the top layer of soil with a fork to break up the crusty surface.

Feeder roots grow near the soil surface, just under the expanded clay mulch.

When soil dries in a pot, it becomes smaller, contracting and separating from the inside of the container wall. This condition is worst in smooth plastic pots. When this crack develops, frail root hairs located in the gap quickly die when they are exposed to air whistling down this crevice. Water also runs straight down this crack and onto the floor. You may think the pot was watered, but the root ball remains dry. Avoid such killer cracks by cultivating the soil surface and running your finger around the inside lip of the pots. Cultivate the soil in pots every few days and maintain evenly moist soil to help keep root hairs on the soil perimeter from drying out.

Do not place containers in direct heat. If soil temperature climbs beyond 75T (24°C), it can damage roots. Pots that are in direct heat should be shaded with a piece of plastic or cardboard.

Feeder roots grow near the soil surface, just under the expanded clay mulch.

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