Spring is in the air. Hurrah! All over my garden the plants are waking up. Crocus and daffodil are in bloom, so are the primroses, the daisies and the pulmonaria. My honey bees are taking pollen into the hive which is a sure sign that the Queen has survived the winter and is laying eggs. On the downside, the lawn needs mowing.
Meadow saxifrage is often the first flower to bloom on a living green roof. These beauties are growing in the Enviromat production fields in Norfolk.
Plants need food to help them wake up
So the plants are waking up after winter. Plants are living things, just like you and me.
What’s the first thing a living being needs after waking up from a long sleep? Me? I need a huge cup of tea followed by something to eat. Without those two things I don’t have a chance of meeting any of the day’s goals (unless those goals are to be sleepy, forgetful, make mistakes and grumble a lot.
Plants are not much different. When longer, warmer days kick start their metabolism, plants need to have a ready supply of water and nutrients. Nipping out for supplies is not an option. They need to have nitrogen, potassium, phosphorus and lots of minerals available in the soil where they live.
Why green roofs are naturally short of plant nutrients in spring
Plants living on the ground have a distinct advantage over their green roof cousins. Deep soil. The more growing medium a plant has beneath it, the more nutrients will be stored in it. Compare that to a green roof – especially a green roof on a shallow substrate. It’s like living next to an understocked corner kiosk vs living next to a superstore.
Healthy plants are more likely to attract wildlife. This buff tailed bumblebee is enjoying a rich supply of nectar from a well fed sedum spurium plant
Soil normally contains lots of soil microbes who pull plant nutrients literally out of thin air. And it can hold onto those nutrients. Storing them away for future use. Green roof substrate is engineered to protect the building against extra weight. It contains less organic matter than soil and fewer microbes. This means that it can’t manufacture a lot of plant nutrients. It’s also beautifully free-draining, so nutrients are inclined to be washed away by heavy rainfall.
After a wet winter, it’s more than likely that nutrient levels on a green roof will be below optimum for the plants.
What to feed your green roof in spring
Applying green roof feed in early spring is absolutely vital. Without it, plant growth is sluggish, weak and below par. I’ve seen green roofs that have gone without feed for several years. They’re not green! The plant coverage is sparse and what plants do survive are severely stressed.
One, carefully timed application of Enviromat Natural Green Roof Feed can make all the difference. You will see lusher, greener foliage. More flowers. More biodiversity. More beauty.