Soil is everything. The texture, diversity of organisms, smell, feel, makeup and human care of soil determine the health and wellbeing of any farm or garden. Soils around the world are being depleted, eroded, degraded, poisoned with chemicals and beaten down by irresponsible farming practices. As sustainable, holistic farmers, our main goal is not only to preserve but to rebuild topsoil.
To some people’s surprise, our work at the farm starts by shifting our focus away from the plants. Because really our job as land stewards is to take care of the soil. In every corner of the globe, there’s some saying to the effect of, “a good grower grows good plants; a real grower grows good soil.”
Plants are just a manifestation of what’s happening underground. If we start with depleted toxic soil, the plants literally take that up, express that, and then we ingest that toxicity. If we raise nutrient-dense dark rich soil, the plants express health and abundance and we take in that goodness. Our job is to create an environment that’s stable, safe and healthy. The rest will flourish.
When soil was initially tested in 2015, we found extremely high levels of lead, inherited not only from the use of lead paint but the previous heavy use of lead gasoline around the city.
It’s commonly agreed that it’s safe to grow crops at less than 22 parts per million (ppm) with the understanding that fruiting crops take up significantly less lead than root and leafy crops. The 2015 soil tests revealed levels of lead varying between 38-251 ppm, making growing directly into the ground not an option, with the exception of fruits and berries. Since 2015, crops have been grown in above-ground raised beds or soil mounds (sometimes referred to by their German name “hugelkultur” — we are shifting to calling them soil mounds to better acknowledge all of the globe’s cultures that use this practice) – all of which have landscape fabric as a barrier to lead-infected soil and are made up of soil that has been tested and brought in by Cero Cooperative, City Soil, Landscape Express or Black Earth Compost – all locally-owned companies.
Soil mounds are the inverse of raised beds. In a raised bed, the wood holds the structure on the outside and the soil is on the inside. In our soil mounds, we stack wood from fallen trees in the middle to create the structure and we pile the soil around that. These mounds have enormous benefits and are used all around the world. Like a forest floor, they provide long term fertility as wood breaks down. They create a good environment for beneficial bacteria, fungi and microorganisms, which support all stages of plant growth. They hold moisture, store carbon, create heat during breakdown, save money on lumber and hardware and they are a great way to mimic the wisdom of a natural and wild ecosystem. What’s interesting is that when we first put seedlings into the soil mounds, the plants seem to struggle. As their roots grow, they hit these roadblocks when they meet the logs and sticks and twigs. But after they learn to navigate those tough areas, the plants begin to thrive! They grow quickly and become super strong, resilient plants for the rest of their lives.
For both the raised beds and the soil mounds, all local soil companies have historically brought a compost/soil mix which has high organic matter and macronutrient contents. This has mostly positive impacts although if percentages of these are too high, plants can grow very fast but with thin cell walls that are then susceptible to insect pressure. From 2018-2022 both raised bed and soil mound tests revealed the soil to be slightly acidic, very high in macronutrients (phosphorus, potassium, calcium, magnesium, sulfur), mid to high in micronutrients (boron, manganese, zinc, copper, iron), low in lead levels (3.9-4.1ppm) and high in organic matter with an average content of 17.2%.
As the farm’s original raised beds (made with lumber and hardware that inherently is more energy and cost-intensive) were breaking down, we decided in 2021 to replace them with these rich soil mounds. With many hard-working young hands from an eager YouthBuild Boston (YBB) cohort, we were able to take down the 48 rotting raised beds, utilize that breaking down wood as a base, add additional wood material from around the site and create 14 new soil mound rows. We took this as an opportunity to reset the main production block with more efficient path sizes and overall layout. In 2022 we were able to re-map and extend our side blocks of soil mounds as well.
As in previous years, we prioritized keeping soil levels high to eventually reduce and eliminate the need to bring in off-site soil. In 2023 and beyond, we will continue to work to build topsoil through different soil mixes, mulches, cover crops and proper soil cultivation methods.
The abundance of flowers isn’t just an attempt to beautify the space, but also to create a key habitat. The flowers we grow, especially the ones in between the vegetables, attract beneficial insects. Not just pollinators – which we need for fruiting crops like tomatoes – but predatory and parasitic insects. We’re inviting in the bugs that eat the bugs that eat the plants! In a quiet moment in the sun, you’ll see hover flies and parasitic wasps buzzing around the flowers and they’re looking for insects like aphids that can cause a lot of damage to our crops. We don’t spray anything on the farm – not even a drop of organic spray – because we’re focusing on creating a whole ecosystem where natural life-and-death cycles are doing the work on their own.
In addition to integrating the flowers into the vegetable crops, a cornerstone of our farming is creating poly cultures. Mono culture – focusing on one or a few crops – is the most unstable system you can make. If you have one crop and that crop gets one disease, that’s the end of our growing system. The Irish potato famine is an extreme example of this.
On the physical layer (on top of the social and economic layers) it was one crop, one disease and the system collapsed. Here we’re growing dozens of different crops – collard greens, lettuces, kale greens, swiss chard, tomatoes, eggplants, cilantro, dill, okra, peppers, squash – all of which create resilience. Flea beetles love eggplants but don’t care about dill. Lettuces are susceptible to fungal diseases that don’t touch cooking greens like collards and kale.Cabbage moths love, well… cabbage, but don’t ever visit squash. So if we do have any pest or disease pressure – which you always will if you grow without chemicals – it may affect one crop but the system doesn’t break down, it stays intact. Diversity equals strength!
Compost earns its title of ‘black gold’ as being the most important medicine for any place where food is grown. High quality compost has the ability to stabilize pH, assist soils in moisture retention and drainage, build fertility and bring in core fungal and bacterial organisms that support healthy plant growth. Because compost is crucial, in early 2018 we installed a simple green “waste” system for all plant material cleared on site and turned throughout the season in three stages. No food waste (leftovers, kitchen scraps, etc.) was put in to deter rodents. In 2021, we were extremely surprised to find slightly higher lead levels in our finished compost after diligently monitoring our compost piles for years. With the help of our extended MA Urban Ag network we were able to connect with soil scientists at Wellesley College who are studying this phenomenon of re-contamination in city soils.
We are now working, with the support of an MDAR grant and Wellesley College, to research and address this further. We will continue to create piles with plant material from lead-free/low-lead soils and with very careful turning, layering and watering, and now more intense monitoring. We still strive to create dark, rich, stable compost where this black gold will be the only fertilizer used on site.
In 2022 we were able to rebuild an effective and beautiful new compost area with YouthBuild Boston and started our compost piles from scratch