Vynnie The Gardener’s 10 Tips for Successful Container Gardening:

1 – Select location in the garden (based on ease of care and morning sun)

Determine where you want to place your pot. This step is about observing your spaces – and not just in the moment, but year-round. This will influence what plants you’ll want to select. Does the area receive morning sun? Does the area receive afternoon – only? Is the area shady in the winter? Does hardscape surrounding the area? Is there a lawn with sprinklers near the area? Will a tree drop litter in the area? Understanding microclimate conditions (humidity, shade, moisture, wind draft, dust, sun, reflective heat) will not only determine what plants you should select, but also the level of care may be involved and what challenges may arise throughout the seasons. This applies to apartments and condos as well. Note that indoors is not an ideal location for most container plants. Given the poor humidity, high drafts, awkward sun exposure and generally low light levels, it takes a determined gardener to be successful growing edibles indoors.

2 – Select a pot (larger is better)

Size matters when it comes to container planting. I call it the two-hand rule; a pot should be large enough that it requires two hands to lift it. Roughly, 24”inches tall or 24”inches wide is adequate for most protected areas. The more sun the area receives, the more non-native the plants used, the larger the container should be. Containers should always have drainage holes, and try to avoid using saucers. They hold water blocking the drainage holes (which are key for air flow to roots). Ceramic glazed pots are best because they insulate well, rarely stain, and take years to deteriorate. The thermal/foam (composite) pots are great too because they are light-weight (size is still key). Avoid thin plastic pots if you intend any plants to last beyond March or November. Anything made of wood will degrade quickly and should be used in full shade or when temperatures are below 80*degrees. I rarely recommend hanging baskets, but if you must, stick to the cool season (November – March). With the proper container selected, color should not be an issue. Set your container in place in the garden or on mobility system.

3 – Set-up watering system (drip irrigation is best)

Until you know how your plants will get watered regularly, don’t do a thing. The easiest way to insure plants get watered is using drip irrigation with a timer. Install ¼”inch drip line (spaghetti tube) through the bottom drainage holes of pot before installing the potting soil. Even if you plan to hand-water, the drip line is a good idea just in case – it’s a real task to install it once everything is planted. Should you go on holiday, you can connect your containers to a drip line and water them automatically. Then, when you return, cap-off the emitters or disconnect the system. Or during the hot summer months when it’s unsavory to go outside to hand-water, drip is your friend. You can easily connect to an existing drip line or set-up a separate drip line for pots only. For hand watering be sure to always have a water hose set up and a couple of watering cans near at all times specifically for this purpose. This minimizes any procrastination for watering. In addition, watering cans help you measure your watering to mitigate risk of over-watering or under-watering. My two secrets tips for watering container plants are (1) to avoid wetting the plants and (2) use filtered water. Water on the foliage will create stresses like yellowing (chlorosis) or brown tips (salt burn). On some waxy leave plants you can even get water spots. So water the soil not the plant (it’s the roots that do the drinking). Filtered water has very low mineral/salt content, reducing the potential for stress, and will minimize degradation and staining on the containers. You can even use a shower filter to hook-up on the water hose.

4 – Select plants for arrangement (combine plants by water requirements)

What is your objective with container plants – Something for the season; Something for the year; Something forever? With that in mind, think fruiting edibles, annuals, perennials, or herbs and native-adapted plants. Phoenix and the southwest is a very unique climate zone, as if container gardening wasn’t tricky enough. So understand the limitations of what is possible will avoid disappointment. During the purchase process, avoid plants that are root-bound (check them at the nursery). If the bulk of the roots are gathered around the bottom of the rootball, just cut away the entire bulk of roots. When you select a mixed group of plants for a container, make sure they all have similar watering requirements and similar growth rates. A hibiscus surrounded by pansies is an interesting combination but could look haggard within a couple of months. Tomatoes and peppers may be a perfect combo for salsa, but will produce a meager batch after the initial harvest. You may even find consistent and lasting success by grouping pots of singular plantings within each. This can simplify watering, fertilizing, maintenance, as well as replacements.

5 – Install potting soil (potting soil only*)

It’s called potting soil for a reason – it’s what you use in pots. Potting soil are often a mix of fine composted mulch, peat moss, and a few amendments such as vermiculite, sands, and slow release fertilizers all sterilized to provide stable and balanced conditions for containers. Regular ground soil (dirt) can contain pathogens, bacteria, and fungi (etc.) that will corrupted potted plants (and the soil) instantly. Generally, you should only add packaged products or known clean materials to your container soil. [*NOTE: Over the course of summer 2008 to spring 2009, I’ve tested using (well-aged) pure compost material in some of my garden pots. This has proven quite successful with edibles and landscape plants in container (outdoors – do not do this indoors). Properly mulched, my pure-compost containers have required less frequent watering (by a day or so) and the plants stress much less (yellowing, burning) than plants in potting soil mix. Plus, I have yet to consider fertilizing my pure-compost containers (nature is the best slow-release fertilizer), still producing healthy growth, blooms, and decent fruit.]

6 – Pumice (the only amendment)

Aside from bugs, pumice is the only thing I add to my container soil mix. It serves 3 key functions: drainage, aeration, and moisture retention. Not to be confused with Perlite (a manufactured product for moisture retention), this little white granular goodness is all natural with a myriad of uses in gardening. For most large containers, mix a high percentage (30%-40%) of pumice into the bottom half of the potting in the container, to increase lower drainage. Drainage is critical when it comes to pots. In our dry weather of Phoenix, pots will often dry out in the top portion of the soil, which we often read as an indication to water. However, the bottom of the pot is still holding water. To continue watering on top of these conditions will eventually cause root-rot.

7 – Install plants (the fun part)

Before installing the plants, know that you’ll need to leave room at the top of the pot about 3”inches deep (one finger depth) for mulch. Don’t tease out the plant roots. This is not necessary for well-selected healthy plants, and can cause additional transplant stress. In the container, set the plant so that the top of the root ball is just below rim level of the pot. Plants that are more deserty (like lavender) can be set a bit higher (because of their need for more drainage). Gently add more potting soil as you add the plants. You should be able to see the top of each plant’s rootball. This will keep the trunk of the plant dry to avoid possible fungus and stem rot. (Make sure your drip irrigation line is still accessible!) With all the plants arranged, fill and pack in soil around the plants. For fruiting plants such as tomato, eggplant, strawberry, bell pepper (etc.), keep the number of plants in the container to a minimum – or just a single plant. Fruiting edibles and major floral plants (roses, hibiscus) require lots of nutrients. Additional plants in the container will only take away from the focal growers, requiring more watering and fertilizing. So you may want to plan for a grouping of single-planted pots for a fuller effect.

8 – Mulch (decorative finish)

The purpose of mulch is to provide some erosion control, help retain moisture and minimize the need to water. Mulch should be a sterile product to avoid bad pathogens. Aquarium pea gravel, packaged fine bark, moss, marbles, and decorative glass are all great. Mulch should be 2”-3” inches deep, which covers the rootball tops of plants. Be aware that mulch will need to be replenished over time and may collect water stains and salt deposits (filtered water is your friend!).

9 – Water

With all the plants installed, time to water. Water just a little, but water about 3-4 applications until you see water flow out the bottom of the container as well as water swelling up in the top mulch. This will assure everything is well saturated. One easy gage for knowing when you’ve watered enough, your watering measure should be almost the same size of you container. Most standard watering cans are about 2 ½ gallons (half the size of a 5gal bucket), which is about the equivalent of an 18”x18”inch container. For hose waterers, count how long it takes to (slowly) fill a watering can. Be sure to water at the soil level and avoid wetting the foliage – the roots need the water. At this point you can finish off your drip line by adding emitters (The drip line out the bottom of the pot, you would connect to your irrigation line). Based upon the scheduled run time length for that zone, you can determine how many emitters it would take to water the container thoroughly. To gage and manage watering, use a moisture meter. Just before you plan to water, poke it in all around the pot, deep and shallow, to gather a range of readings and water when plant is getting dry. If the plants are showing signs of droop during the morning, it’s likely they need more during watering or need to be watered more frequently. Keeping the watering schedule consistent and balanced is the best way to produce quality succulent edibles.

10 – Pruning and care

The best way to keep plants healthy is to prune. Pruning dead or wilty parts keeps the plant from attracting pests, as well as the occassional water spray to remove dust from leaves to the worst violators scale and mites. Removing spent or un-pollinated blooms can promote new growth. In addition, selectively reducing the number of blooms will help produce fewer but more robust fruit. Herbs and greens benefit from pruning to produce tender new growth, ideal for fresh cooking. And remember, harvesting is a form of pruning. Fertiling can be tricky if you want to keep organic, otherwise, simply follow the manufacturer’s instruction on the product package. A good holistic approach to fertilizing is to create compost tea, which can be used in watering but is also beneficial to spray on foliage, to feed the plant and stave off pests. Aged compost, actual tea and coffee are great for this concoction. Gather it all in an old t-shirt or cheese cloth and tie off the end forming a ‘tea bag’. Soak this in a bucket of water overnight, then remove, and the bucket is filled with all natural liquid fertilizer.