Our Specialist Solar Seed Mixes

We have supplied specialist solar seed mixes to over seventy solar farms or parks in the UK, most of which we have seeded too.

These are usually mixes of British native wild flowers and grasses in combination. Seed mixes like this significantly enhance biodiversity on what was typically agricultural land, and are also relatively easy and cheap to manage. This is particularly true if the sites are grazed through the winter.

Solar seed mixes are also – in our experience – surprisingly easy to establish. The sites we’re working on are usually low grade land, so competition from aggressive weeds is less than you might think. In any case, starved of chemical enhancement, “fertile” soils often become infertile very quickly!

The caveat to these comments on ease of management and establishment is that is that weed management has to be done promptly and pro-actively. We sometimes find that neither budget nor management system allows for this.

Solar site in Hampshire, poor calcareous soil, 6 months after seeding (freakishly good!)
Solar site in Hampshire, 6 months after seeding, poor calcareous soil. Freakishly good result, using local direct harvest mix.

There is absolutely no “one size fits all” approach, as you might think if you read the blurb on some suppliers’ websites. There’s a whole range of options, to fit budget and site specifics. We work with ecologists and developers to come up with an ecologically appropriate solution specific to an individual site, which won’t break the bank.

There are some guidelines which we follow, however.

1. Always, always use seed with documented UK provenance.

2. Always, always use wild species, not agricultural cultivars. Cultivars of wild flowers, like Bird’s foot trefoil, don’t last very long and don’t benefit wildlife to the same degree that the wild plants do. “Wild flower” and grass cultivars grow much faster and much bigger; they will need a lot more cutting. Buying seed mixes consisting of agricultural cultivars is a false economy.

3. If possible, use a direct harvest seed mix with local provenance. This will be more appropriate, produce better results, and – frankly – look good in terms of corporate PR. These mixes are also typically great value for money, given their high floristic content.

4. Don’t be tempted to seed at less than 30kg/Ha – 40kg is ideal. There are some folk who recommend seeding down to 20kg. This won’t give you a reliable result.

5. Always find an experienced seeding contractor (like one of ours!). Sowing wild flower seed is a very different thing to drilling wheat.

6. Try to use a minimum of 80:20 grasses to wild flowers, if your budget allows. Sometimes specifications are 90:10 or even less, which mixes are cheaper but much less effective.

7. Don’t be tempted to use commercial “bird seed” mixes. These look cheap, but have limited value to invertebrates and require regular reseeding. A traditional wild flower meadow mix will not.

8. Look at the design of the site. The width of the arrays themselves as well as the alleys between them can dictate the solar seed mixes which will work best.

9. Manage expectations. Wild flower meadows aren’t built in a day. The longer they take to establish the more diverse they can end up.

10. Try to ensure the site operator follows an appropriate management regime.

Seed mixes for solar sites
Site in Oxfordshire, 18 months after seeding. Difficult, heavy soil.

Solar Farms – Biodiversity Hotspots?

Solar farms, or parks, are going to come in for a lot of flak. Photovoltaic panel prices are a third of what they were three years ago. Generous government support and ambitious targets mean that they’re sprouting all over the countryside. For developers and landowners they’re a no brainer, offering spectacular guaranteed yields. They seem to be a much better solution to meeting our renewable obligations than wind farms, too.

Everyone loves the idea of renewable energy, but the reality can be less attractive. Particularly before landscaping, solar farms can look pretty enormous and industrial. The visual impact of solar farms is a difficult thing to assess, and provokes fierce argument. A proposed site might look fine on a map if it’s not visible from any “important” or regularly used sites or footpaths. If you live in the one house directly overlooking it you might feel differently.

Many developers are motivated by purely economic interests and fail to engage local communities. Worse, they just ignore them, knowing they can get planning permission on appeal if necessary. The planning process is struggling to balance local opposition with national policy. We can take some of the heat from this process by improving the way solar farms are established and run.

Biodiversity in solar farms
Is this a biodiversity hotspot?
Mitigation requirements are generally modest, and mostly relate to hedges and hedge planting. They should be more ambitious. Sure, reinforcing, planting and letting hedges grow is helpful, but why not do more? Solar Farms actually represent a great opportunity to create biodiversity hotspots. The green deserts they replace are generally “improved grassland”, and have very limited value for biodiversity – contrary to most people’s perception. Solar farms, surprisingly, can be much more interesting.

For a start solar farms are fenced, which prevents destructive larger mammals (including humans!) getting in. This is great for flora, reptiles and ground nesting birds, for example. There’s also typically a margin between a surrounding hedge and the security fence. Why not establish a floristically enhanced margin here? Or if you were keen to encourage owls, for example, plant tussocky grass to help the vole population.

Currently, the areas between and around solar panels in most sites are either sprayed off with herbicide or cut regularly, to keep grass and weeds from obscuring the panels and scrub from getting established. Why not have grasses and wildflowers there instead? Although they will actually need less management, planners should require a management plan for these areas too. The aesthetic and environmental gains are obvious. There are also economic advantages; the cost of maintaining a carefully planned wildflower and grass mix is much lower than repeated large scale spraying or grass cutting.
These areas can also be tweaked to encourage particular wildlife. Perhaps the local community would like to encourage skylarks or a rare type of bumblebee (which is happening at one of the sites we’re involved with). The plant species can be selected and managed to suit.

The layout of solar farm panels can be helpful for biodiversity, too. Directly below them is dry, shaded and sheltered. At the base of the panel there is water runoff and more light, and in front of each row light but less water. These micro-habitats are ideal for encouraging a tremendous diversity of flora and, ergo, wildlife.

When stipulating planting schemes, planners can also be picky about provenance. It’s a great opportunity to help British suppliers of plants and seeds – like Habitat Aid! – as well as to do the right thing ecologically. Let’s learn from Ash Tree dieback. Hedge plants for solar farms shouldn’t just be native species but sourced from British stock grown in Britain. We can be even more local with wildflower and grass mixes. We can supply seed harvested from sites all over the country.

There are other potential uses for solar farms. Use orchard trees as part of any screening planting – and why not plant them with local varieties of fruit tree? I know of one site where they’re rearing queen honeybees behind the fencing, undisturbed by vandals and badgers. This stuff isn’t unreasonable or unrealistic. We are partnering two of the best solar farm developers in the country who are doing just this kind of thing:

The Shock of the New: Contemporary Homes and Solar Farms

The Shock of the NewI bet that the majority of folk who stop in front of our new house* aren’t wondering how many architectural awards it might win. I bet they’re wondering why someone in planning didn’t stop it being built, because they think it’s gopping. Each to his own; we (obviously) think it looks great. There are a couple of morals to this story, however.

First off, it should strike the gawpers that they should be that someone in the planning process trying to ensure we carry on replicating 19th century houses. The Parish Council had two planning meetings to discuss the house, the first attended by one person (me) and the second by three.

Secondly, “the country” is an environment where people live. The more prosperous it is, the better those people will be able to look after it. “The country” isn’t the exclusive preserve of retirees from the suburbs or second homers, who would, typically, like to live in an Austenesque idyll (or Poundbury!). It has to move on. I’m absolutely not saying we should rip up the restrictions on development that we have in place and go all utilitarian. Our house is not only wonderful to live in but costs nothing to run. We generate more electricity than we use and heat it and cook with wood. This doesn’t mean it should automatically get planning permission. I am saying that when the CPRE objects to faster rural broadband on the basis of disfiguring “new overhead lines and broadband cabinets blotting our finest landscapes and villages” I get cross.

The explosion of solar farms that’s happening across our landscape at the moment is another case in point. The combination of government incentives and cheap photo voltaic panels means there will be thousands of acres of them put in over the next two years. There will be some appalling cases, but I hope the planning process will generally be robust enough to stop development where it is damaging or unsightly (if the gawpers get themselves along to the right meetings). In contrast to wind farms, solar farms can also offer a brilliant opportunity to create attractive and valuable new habitat.

We are working with Solar Century and – I hope – another large scale developer, who are determined to do just that. They are putting in wildflower meadow areas and new native hedges on a large scale, and going the extra mile to make sure they are establishing the right plant species and that they will be managed sensitively. We’ve hooked Solar Century up with the Bumblebee Conservation Trust, who will be helping them out.

*which is, frankly, getting a bit weird. Also, when I greet gawpers with a friendly hello I feel a bit miffed when they drive off at speed.