nettles (Urtica dioica, Urticaceae) are herbs with an appreciation for wet feet. Depending on your climate and garden habitats, containers can help provide the extra moisture needed for their thrival. Plants preferring well-drained soil: Consider adding very coarse sand and/ or pine bark fines (see notes below) to increase the drainage of the soil. Perlite is also an option, although it is less sustainable. Water only when the soil dries out. If you are in a climate with extra rainfall and humidity, you may want to keep these pots out of the rainâ€™s reach. I keep arid climate plants in a sunny spot on my porch or in my greenhouse. Be careful to only water the soil and avoid watering the foliage, as these plants are more susceptible to fungal diseases. Ma huang (Ephedra sinica, Ephedraceae), prickly pear (Opuntia spp., Cactaceae), rosemary (Rosmarinus officinalis, Lamiaceae), lemon verbena (Aloysia citrodora, Verbenaceae), garden sage (Salvia officinalis, Lamiaceae) and white sage (Salvia apiana, Lamiaceae) are a few medicinal plants that appreciate drier soils. Plants preferring shade/part-shade: If you are trying to grow temperate or cool-weather plants in an especially hot climate, providing afternoon shade will often keep the plant happier. If you donâ€™t have shade in your garden, you can grow many woodland medicinals in containers on a shaded porch, deck, or even in the shade of your house. Gotu kola (Centella asiatica, Apiaceae), Jiaogulan (Gynostemma pentaphyllum, Curcubitaceae), wild geranium (Geranium maculatum, Geraniaceae), black cohosh (Actaea racemosa, Ranunculaceae), blue cohosh (Caulophyllum thalictroides, Berberidaceae), goldenseal (Hydrastis canadensis, Ranunculaceae), are some of the plants I have seen grow well under shade in containers. Sensitive herbs: Cold-sensitive perennial herbs can be grown outdoors in a pot during the warmer months and then brought indoors or to a sheltered location when the weather grows colder. Many of these plants will go dormant during the winter, and can be overwintered in a basement, attic or warmer sheltered spot. In contrast, some of these hot-climate plants will require sunlight during the winter: place them in a greenhouse or in front of a south-facing window. This is a lovely option for those of you who
live in climates where it freezes infrequently. Lemon verbena (Aloysia citrodora, Verbenaceae), white sage (Salvia apiana, Lamiaceae), lemongrass (Cymbopogon spp., Poaceae), gotu kola (Centella asiatica, Apiaceae), ginger (Zingiber officinale, Zingiberaceae), turmeric (Curcuma longa, Zingiberaceae), bay laurel (Laurus nobilis, Lauraceae), Aloe vera (Aloe spp., Xanthorrhoeaceae) and Citrus (Citrus spp., Rutaceae) are some of the tenders, which you may choose to baby a bit.
Retired ceramic bathtubs, sinks and toilets: These are some of the greenest container options available as they are often destined for the landfill or available for cheap. They are long-lived, resistant to cracking from temperature fluctuations, and often provide a sizeable growing area that holds moisture quite effectively. Plastic pots: Black nursery pots or plastic buckets are often cheap or free, and lighter than other pots, with an increased ease of portability. The downside of plastic vessels includes their shorter lifespan and the heavy environmental toll in their creation. Often landscapers throw away large pots, so reuse helps keep them out of landfills. I have concerns about the possibility of chemicals leaching from the plastic and entering the plants via the soil substrate. Many of the chemicals used in the manufacture of plastics are powerful endocrine disruptors. This is an issue that has kept me up at night with worry about the possible contamination of medicinal herbs grown in plastic containers in my own nursery. Terra cotta: Terra cotta, or clay pots wick away moisture quickly so they need to be watered more frequently than pots made from other materials. These pots will also crack and break with the expansion and contraction of freezing soil, so they need to be emptied and protected from moisture during the winter in temperate climates. Terra cotta pots can sometimes be found used but the new pots are typically imported from Asia. However, there a few domestic producers still around, but their pots are typically more expensive and not widely available.
Published on Jan 30, 2013