Luckily, nature has a solution for us - mycorrhizae. Mycorrhizal fungi, just like all fungi, cannot grow without getting an food source (they are heterotrophic, like animals). For this they need the roots of plants to provide them with sugars. In exchange, the mycorrhizae greatly expand the surface area of the of the "roots" by attaching and allowing the roots to collect water and nutrients from more numerous fungal filaments. This is seen below - with the corn root appearing much larger than the mycorrhizal fungal root (meaning the corn gets a larger rhizosphere).
|A microscopic view of an arbuscular mycorrhizal fungus growing on a corn
root. The round bodies are spores, and the threadlike filaments are hyphae. The
substance coating them is glomalin, revealed by a green dye tagged to an
antibody against glomalin.|
Photo by Sara Wright - courtesy of USDA, public domain
Although we didn't have the resources for a large experiment, we decided to plant two peat pots of our garden vegetable seeds indoors, one with mycorrhizal fungi, one without. We would then try to keep all other variables constant, including light (from overhead grow lights), as well as water and space for the plants. You can see our results below
|Kellog's Breakfast heirloom tomato grown with mycorrhizae (left) and without (right) with same amount of light, water, and soil. Clearly the peat pot with the mycorrhizae has a much higher germination rate and faster growth. Photo taken on 3/16/16|
|Carnival peppers, with mycorrhiza added on left and none on right - again clear germination and growth advantage of the mycorrhiza added group|
|Bell peppers, with mycorrhiza added on left and none added on right - again, the mycorrhizal group had better germination and growth, although not quite as pronounced as the Kellog's Breakfast tomatoes and the Carnival peppers.|
|Amadeo eggplant, with mycorrhiza on left and none on right. We are not sure why germination rate is higher with the non-mycorrhizal group for this plant.|
Updates: April 3, 2016
|Amadeo Eggplant - left with mycorrhizae, right without - this is our only plant that hasn't done better with mycorrhizae|
|Tomatillo with mycorrhizae on the left and without on the right - the tomatilloes with mycorrizae have a significantly higher average height|
|Bell pepper - with mycorrhizae on the left and without on the right - the pepper with the helpful fungus is clearly much larger overall|
|Carnival pepper, grown with mycorrhizal fungus on the left and without on the right - the pepper with mycorrhizae is about 20% larger overall|
|Two Sweet, Long, Tall Peppers - the left with mycorrhizae (looking quite comfortable and tall in our desk chair), the right without mycorrhizae and barely an inch tall|
We used "Mykos" brand Rhizophagus intraradices available on Amazon here. We used only a very small amount of mycorrhiza (we used a forceps/tweezers to grab about 1/2 inch of mycorhizzal granules between the two parts of the tweezers). We believed that the mycorrhizae would of course proliferate on their own, and there was no sense putting down more mycorrhiza than what could immediately surround the new plant roots. As the mycorrhizae are somewhat expensive, this also allows us to conserve resources.
What can we conclude from our miniature experiment. Well - first, not everything grows better with mycorrhizae, at least not the type we used (see below). Eggplants, in particular seem to grow more slowly with mycorrhizae than without. Tomatillos did not seem to have much difference between the control and test group, but Kellog's Breakfast Tomato grew a great deal more with mycorrhizae.
The consistent improvement we saw in different pepper varieties with mycorrhizal fungi, however, was impressive. Our sweet, long tall peppers in particular did much better with mycorrhizae. We plan to use mycorrhizae when planting peppers in the future. For commercial growers who happen to be reading this - growing peppers with mycorrhizae and with the Waterboxx may be an ideal, low water, low work way to have large harvests of high value goods. For the average gardener in a dry climate - the Waterboxx and mycorrhizae may allow you to not water your peppers at all after outdoor transplanting - all while growing fresh, delicious, sustainable produce.
We will have other blog posts with our results after outdoor transplanting. If you would like to know more about mycorrhizae (from an academic source), see here. If you would like to know more about the Waterboxx and how you can garden without ongoing watering, see here.