Plants and dry soil usually go together like peanut butter and french fries, but some select plants prefer quick draining, gritty, nutrient-poor soil. It’s what they’ve evolved for! In fact, many of our favorite herbs are native to the Mediterranean basin – where the soil is sandy, dry, and chalky and the summers are hot and dry. This origin tells us a lot about the ideal conditions for healthy, long-lived, flavorful plants.
What are the Mediterranean Herbs?
Herbs that are busy or sprawling with woody stems are called “Hard” while herbs that are entirely tender are called “soft”. They are used slightly differently in cooking, and hard herbs can endure slightly harsher conditions, but they can all be grown in the same situation and thrive.
Rosemary, sage, thyme and oregano make up the hard herb category. With their gray-green foliage and shrubby stature, these “hard herbs” are easy to imagine on a sunny Mediterranian hilltop and can thrive in poor soil. They grow a bit slower and concentrate essential oils in their leaves, so are added at the beginning of cooking to release all of their bound up flavors.
Based on their looks alone these herbs (Dill, Cilantro, and Chives) aren’t an obvious fit for dry soil, though they grow and taste better with limited water. They grow faster than the Hard herbs, are shorter-lived plants and, in the kitchen, are added fresh at the end of the recipe.
What’s the best planter for these herbs?
Based on their open, free-draining native habitat, Mediterranean herbs seem like a good fit for a pot filled with the right dirt, but the performance of a smartly designed self-watering planter is tough to compete with.
Free Draining Pot vs Self Watering Planter
The main concern with Mediterranean herbs is that their roots sit in soggy soil – they aren’t well-adapted for soaking in water and are prone to rotting. On the other hand, these plants are not fully drought tolerant and need consistent access to water. In nature, they develop big root systems to access limited water as the soil would dry out between rain. Mimicking this with a pot and soil takes a very large container! The right self-watering planter can provide more consistent conditions – and do it in a lot less space with a lot less to maintain.
Self Watering Planters: Wicking vs. Ceramic
Some self-watering planters are able to maintain perfectly consistent, slightly moist soil, while most have hardly any control. Systems that rely on a wick (the vast majority) tend to have soggy soil and roots that grow directly into the reservoir. A growing number of self-watering planters are instead using a semi-permeable ceramic membrane to control the soil moisture. It’s a mouthful, but basically, the planter will only let more water in once the soil dries out past a certain level. This gives us a fine degree of control and there’s no way for the roots to get into the reservoir. If you want to geek out even more on SWP’s check out our R&D tests [coming soon].
How to Grow Mediterranian Herbs in a Ceramic Self Watering Planter
The instructions below are most relevant to our upcoming Self Watering Planter (to be released summer 2021) but will work for most ceramic self-watering planters. There are a couple of current options on the market, including Wet Pots, COSWIP, and the Great Northern. Of these, the Great Northern keeps the best soil moisture levels for Mediterranean herbs.
The ceramic material used in the different planters lets in different amounts of water, but the wetness of the soil will be directly proportional to how high you fill the reservoir. Other factors like how big your plant is and how much light it gets will impact the water level that you’ll want to fill the reservoir to – so it’s best to pay attention to the soil. If the soil surface is ever wet, you’ll know it’s filled too high. Let the water drop down until the soil surface dries – this is your “high fill” line for mediterranian herbs. Let the water level drop to the bottom of the reservoir between refills.
While plants are amazingly adaptable, looking at where they originate from points us to the best soil for long term health. All the Mediterranean herbs love chalkly, porous, alkaline soil, and may not taste very flavorful if grown in soil that’s too rich. For off-the-shelf options, cactus mixes tend to work well. For an easy DIY mediterranean soil, start with a regular potting mix and add in ⅓ vermiculite or perlite.
As they are accustomed to “poor” soils, none of the Mediterranian herbs need very much additional nutrients and range between being light feeders and very light feeders. Depending on how rich your starting soil was, it can be upto a year before you should add nutrients. Once its time, (you may notice pale leaves) add slow release fertilizer, following the manufacturer’s “light feed” dose recommendations.
Mediterranean herbs like their personal space. They are used to open areas with ample air circulation and space for their roots to spread.