This month at the Brockwell Park Community Greenhouses we’ve been ‘earthing up’ our potatoes. This process protects early shoots from frost damage and ensures that the developing potatoes aren’t exposed to light (which turns them green and poisonous.) It’s a simple process – once the stems are about 10cm tall we create a ridge of earth to cover all the shoots completely. As the stems continue to grow this process needs to be repeated several times.
Now the soil is finally warming up after a very cold April we’ve been directly sowing herb seeds into the kitchen garden. To spread risk and compare the pros and cons of both methods we will also start some off in modules in the greenhouse. Generally speaking the advantage of direct sowing is that the herbs should not have their growth checked by transplanting, and the disadvantage is that they well be exposed to more risk to attack from pests by being outside in the garden at the young, vulnerable seedling stage.
Some of the annual herbs we will be sowing are borage, tarragon, rocket and agretti. The Italians know and like agretti and call it ‘monk’s beard’. The Latin is Salsola soda, which reflects its historical importance as a source, once burnt to ashes, of sodium carbonate, which is used in the manufacture of both glass and soap. Agretti can be found growing on sandy seashores around the Mediterranean basin. It is so salt-tolerant that you could irrigate it with seawater if you really wanted to!
In the vegetable beds the beetroot and chard seedlings have germinated and we’ve started to thin out some of the rows of seedlings. Thinning out is a process by which we reduce over-crowding in the row by removing some of the smaller plants to give the larger plants more growing space. This enables us to grow healthier plants which have sufficient space to develop into sturdy plants that will give us better yields later in the season. However the thinned-out plants do not need to go to waste as they can make tasty salad leaves when added to salads. In the lower beds Team Tomato have been hard at work planting out dozens of tomato plants. We’re very sheltered there so no risk of frost now.
We’ve also been sowing the seeds of the plants that like warmer temperatures such a squash, gherkins, courgettes and cucamelons. With the exceptions of the cucamelons, these are quite big plants and as we do not have much space for them in the greenhouse we aim to sow these seeds about four to six weeks before they will be ready to be planted outside, after the risk of frost has passed.
A note on Pumpkins and Squash….The terms ‘pumpkin’ and ‘squash’ are rather loose but both refer to annual plants which usually have a trailing habit. They are divided into ‘summer’ and ‘winter’ types, depending on when they are harvested. Generally speaking, summer squashes are harvested and eaten (usually fried or boiled) while still young, whereas winter squashes and pumpkins tend to be baked or stored cool and dry for future use. Summer squashes such as courgettes and patty pan are normally white-fleshed, while pumpkins have orange flesh.
We continue our work on the fern bank, adding new logs to enhance the front edging of this bed, checking the irrigation system is working and moving a few more ferns to more spacious locations further up the bank.
We’ve also been enhancing the children’s mud kitchen area by creating some wildlife friendly hedging to provide more screening from the park side path. A very simple way of creating this kind of hedging is to buy one-year-old trees called whips. There are a number of plant nurseries that grow this kind of bare-root hedging which consist of trees that have been field grown, lifted when ready during the winter season of dormancy and have had the soil shaken off them. They are available during their natural dormant season (November – April) and are the most cost effective way of creating a hedge.
You can buy bird friendly native hedge mixes made up of species including hawthorn (Crataegus monogyna), sloe ( Prunus spinosa), field maple, myrobalan plum, bird cherry, hazel, common alder, guelder rose, dogwood, elder and wild crabapple. This is a mixture of native species that will grow into a dense hedgerow encouraging birds and many other forms of wildlife to make their home in your garden. Hedges like this will provide flowers, catkins, nuts, berries and autumn colour, as well as providing shelter from the wind.
In May, both at the Greenhouses and in your own greenspace:
- Make the most of your water. Climate change means that more and more of our precipitation comes in big storms, where the water will run off dry, hard soil without soaking in. Water early and late to get the most out of your water and recycle water whenever possible.
- Watch out for late frosts, it could still happen. Protect tender plants by taking them inside (if you can) or covering them with soft material like horticultural fleece.
- Get on top of your weeds now! If you’ve got a hoe that’s a good way of nipping out the new seedlings, or you can’t beat a good old-fashioned finger and thumb. Make it a mindful exercise now (perhaps with a cup of tea and a podcast) and you’ll thank yourself later in the year.
- If you decide you must trim your hedges, make sure to look for signs of nesting birds first. Remember it is against the law to interfere with an actively used bird’s nest. If you can wait, please do – the RSPB recommends not cutting hedges between March – August.
- May is a good time to do things to support your existing perennials like staking to provide support, feeding plants (especially container-based ones) and ‘training’ plants to a particular shape by gentle pruning.
- It’s not too late to plant and sow! Sow Nasturtium, Cornflowers, Nigella and Sunflowers for colour and harden off Sweet Peas (for colour and their wonderful scent). Broad and Runner beans, Peas, Carrots, salad crops, Leeks, Onions and Garlic could all go in your veg plot, and once the last frost is definitely (definitely) passed it’s time to plant your Tomatoes out in a sunny spot.