An important part of our guerrilla gardening manifesto is to help the planet, not harm it. But when you're getting started, it can feel overwhelming trying to work out which plants or practices will support ecosystems, and which could potentially be harmful. Then there are concepts like 'heirloom seeds' and 'peat free compost' that you might not have even heard of, let alone know why they matter!
In this guide, Poppy Okotcha comes to the rescue – explaining the basic do's and don'ts when it comes to creating an eco-friendly guerrilla garden.
DO think about where your seed comes from
Maintaining diversity in seed is super important because diversity=resilience. But in the last 100 years, 90% of UK veg varieties have been lost. Most large seed sellers only offer a limited number of varieties of seed, and produce their seed in hot, dry parts of the world (such as North Africa and the Middle East), using industrial, chemical agriculture, with poor human rights observation.
Choose not to support this industry. Sow seed grown in the relevant climate, and safeguard seed diversity by:
Saving seeds from your plants
Swapping seeds with other local growers
Joining a seed library, such as the Heritage Seed Library
Choosing to grow heritage, local seed varieties
DON'T sow F1 seed
F1 seed is the result of breeding two seed lines to create progeny with certain traits. While this can be super useful, seed saved from F1 plants (or F1 plants that self-seed) will give a daughter plant that doesn’t resemble the parent plants, and will generally be very poor quality.
By not sowing F1, you'll be able to save your seeds, meaning you won’t have to buy them again! Or even leave some plants to self-seed in situ for a more hands-free approach!
DO grow heirloom/heritage seed
Heirloom and heritage seed is seed that can be traced back, having been grown, saved and passed down for many generations (usually 50 years) within a family, community, region or project. This can offer brilliant adaption to local growing conditions and huge genetic diversity. Heritage seed has often been bred for better flavour and nutrient density over aesthetics and high productivity. Heirloom and heritage seen is open-pollinated.
DO choose open-pollinated
Open-pollinated seed produces plants that can be pollinated by a natural mechanism, such as self-pollination, insects, birds, the wind – or even a human with a paintbrush! Generally, their progeny will be like the parent plants, with some natural, healthy variation. This makes them great for seed saving.
DO choose plants that will add fertility
Plant dynamic nutrient accumulators, like comfrey and alkanet. These are plants that bring nutrients up from deep in the soil – out of reach for many plants – which they store in their leaves and eventually return to the soil surface as the leaves rot down.
Muddle legumes in throughout. These are plants in the pea family such as beans, vetch, clover – they’ll fix nitrogen into the soil.
DO choose plants for wildlife
Think of wildlife as gardening assistance; they help keep the space healthy. They can: aid in pollination; act as a natural, chemical-free pest control; provide fertilisation; improve soil health; and support ecological balance.
Earthworms, toads and frogs, birds, bats, butterflies, bees and ladybirds are all great garden assistants. And, of course, supporting biodiversity is a great thing to do in itself!
DO sow native, local meadow mixes
If you choose to grow a meadow, have a little search for a meadow mix that is "native", meaning from your local area. This will prevent invasive species crowding out local wildlife, as well as helping your grasses and wildflowers to thrive in the local environment.
DO identify and research “weeds” before you remove them
Many common “weeds” are actually brilliant medicinal, edible, habitat and pollinator plants, that condition the soil.
Before removing all the green in sight, try to ID the plants. Ask a friend, use an app (“LeafSnap” is free!) or a handbook. Find out what they offer the space and see what they look like through the seasons – they might have wonderful flowers later in the year. Keep as many “weeds” as you can.
Check out More Than Weeds, a project aimed at changing our perception of urban plants growing on walls, pavement or tree pits. They use chalk to label "weeds", like this.
DO plant plants that the community will benefit from
Consider plants that other people will benefit from. They may smell good, look wonderful, be edible, or have medicinal properties. Remember, guerrilla gardens are ones you create in public places, with purpose.
DO focus on diversity
Diversity=resilience, so try out "companion planting" in polycultures. This is selecting a range of plants that get along well together, supporting each other’s growth. Possibly the most well-known are the "Three Sisters" grouped by the Iroquois, Cherokee, and other Native American tribes.
DON'T use peat compost
Peat comes from peat bogs, which are very special habitats that sequester loads of carbon. They are formed over thousands of years so are precious and finite. Mining peat for compost releases CO2 into the atmosphere and destroys valuable ecosystems, including many of the rare and endangered species that live in and around ancient peat bogs. Avoiding peat compost is easy: simply look for compost that's labelled "peat free".
DO test manure before spreading
Aminopyralid is a broad leaf herbicide used to kill “weeds” in hay fields. The hay is fed to livestock (e.g. horses and cows), they poop it out, and the aminopyralid stays in tact. As it spreads on a growing space, any broad-leafed plants (not grasses) will become sick and slowly die.
Either avoid using manure full stop, or test before spreading. Plant a couple of broad beans in the manure and others in compost. Wait for them to grow. If it is contaminated with herbicide, the leaves of the manure-grown beans will develop deformed (you can use the others for comparison).
DO build the soil
The soil is the foundation for a healthy grow space. Check the condition of your soil. If the soil is compacted, grow pants like mustard with roots that will help break it up. Add organic matter – mulch – to improve soil condition and keep the sun's rays off it (bare soil is a wound in the Earth!)
DO mulch with organic matter
Mulch is a material that is spread on the surface of the soil. You can use unlaminated cardboard, newspaper, compost, leaves, wood chips, well-rotted manure, wool carpet, or even old cotton curtains.
Mulch will protect the soil surface (ensuring the structure of the soil is hospitable for the precious soil life), insulate, and reduce evaporation (meaning less watering). Ultimately, it will rot down, feeding the soil life and your plants.
This is a way of growing that disturbs the soil least and so maintains healthy soil life. It also means no back-breaking digging (unless your site needs lots of enthusiastic perennial weeds removing in year 1, such as bindweed and brambles!)
DON'T use chemicals
Chemicals used on growing spaces may temporarily solve one problem, but in the long run destabilise ecosystems, causing long-term issues, and often ultimately chemical dependence. They’re also expensive and often toxic to us too!
Instead of relying on chemical "fixes", focus on creating a diverse space (lots of different plants) with healthy soil. Healthy plants aren't bothered by disease as much, and natural predators should take care of any pests. For example, plant flowers like yarrow and fennel: hover-flies love them, and their larvae eat aphids. No pesticides needed!
DO use organic everything (if you can)
Organic seed, compost, plant feeds! While 'organic' often sounds like the more expensive option, as you build an organic practice, you become more self-sustaining – being able to seed save, keep off pests and feed the soil with no external things needed – ultimately saving money in the long run.
DO work with the space and what’s already there
Ideally, choose a spot that you’ve seen through all the seasons. That way you can change the site with sensitivity to what is already there and which creatures may already call it home.