ROOF TOP VEG PLOT

Raised Beds

Be they grand or modest, all potager gardens have one thing in common.  Their beds, generally but not always rectangular, are  invariably surrounded or supported by something. The nature of this edging is one of the most important decisions a new gardener must make. 

Size
The square foot garden, that is in my humble opinion, a rather anaesthetised version of the classic potager, is divided into foot square, or 30cm square sections.  A bed can be 90x120, 120x120 or as in my case 60x240cm.  Oh woe is me, that when I designed the garden, I forgot about edgings.  Allowing for the width of a wooden or brick upstand, the thickness of a fringe of herbs or the bulk of a box mini-hedge, can make the minimum size much larger.

In the beds where I have placed edging plants I allow about 15cm for the mini-hedge.  But even this tiny size will overshadow the first few centimetres of soil.  In a 60cm square, edged all around the actual growing space could reduce to 30cm square.  

Do not reject attractive edgings because they take up space.  Edgings protect against winds, distract pests and attract pollinators.  They also look pretty.

Neat, well trimmed herbs chosen for their flower and leaf colour surround less showy crops. legumes. Credit BHG.com

Layout
The modern French potager plot is often laid out as a series of 30cm square vegetable patches.  It is called the 'potager en carre'. But more often than not this rigid arrangement is softened by provision of an extra 15 or 20cm on one, or all sides to allow for an annual, perennial or herbal edging.  I've drawn some example layouts for you below.  

1. Four 90cm wide plots with the narrowest paths between them. In my view 50cm is about as small as paths can be.  My paths are 60cm wide.  Here the centre strips would be nice as perennial herbs, like lavender, or annuals like marigolds. An extra strip across the back, the norther side of the garden, allows for a protective trellis of climbers or fan trained fruit trees.
   
   
2. Four 120cm square sections, each with with an extra 20cm on two sides and 80cm wide path between the beds.  Each bed could be edged with a contrasting vegetable or herb. Red basil and unheaded lettuces both make good edgings.  Choose low growing species to avoid overshadowing.
   
   
3. This is a more elaborate layout with four 120cm beds, wider paths between them and some infill pieces to east and west.  The most favourable southern aspect has been filled in with another bed, 60cm deep.  It is important to be able to get to the farthest corner of each bed without needing to stand on the soil, hence the setback in the centre.  This would be a wonderful position for a bench. The central, circular bed might have something like a specimen standard rose in a pot, fringed below with a single vegetable cultivar.Chervil or parsley, would make a nice annual fringe, alternatively a succession of cut and come again red leaved lettuces would complement a magenta rose. Alternatively, as illustrated below, fill the urn with pollen rich flowers like Buddlea, to attract butterflies right into the heart of the garden.
   
   

   Versions of 1,2 and 3 above realised in very different gardens. Credit: cestlaviebytam.blogspot.com, ellenodgen.com

Construction
My beds are 15cm high, built on top of wooden pallets that allow drainage below.  The timbers are untreated softwood, 18mm thick, which for smaller beds are light enough and strong enough to sit on my rooftop.  Ask me in ten years’ time whether that was the right decision.  It is also quite easy to get 225mm or 300mm timber boards in DIY shops.  If you are making the beds on solid ground, the extra depth of soil might be worth it, but for me the weight was the limiting factor.  The wider the boards, the thicker they must be to stop bowing.  In between the raised beds I have placed 60cm square timber decking. These disguise the edge of the pallets.  At the time it was the architect in me that made the whole thing modular, using the 60cm squares as my module.  However, now I am starting to change things around, a grid layout has proved very useful.  It is quite easy to take things out, even to move an entire bed, without destroying the integrity of the whole arrangement.

An early shot of the newly planted beds

There are hundreds of proprietary raised beds on the market, ranging from plastic and cotton bags, plastic clip together systems, metal struts and very solid timber systems.  There are also natty little willow fences that you can use to edge the more unsightly ones.  You could also use recycled boxes, Alys Fowler advises Champagne boxes and I’ve noticed some very cheap lattice boxes in Ikea, which come with a fence type slatted backing, which would be ideal, in the right location. 

 

Ikea Applaro bench with wall panel and shelf.  The lower box, would make a good planter. Line it with black horticultural liner.

 

My plain timber beds looked a bit utilitarian before things started to grow.  But it is the plants you look at not the box, especially if you edge very visible beds with trailing flowers.  So I would advise not getting too carried away and not spending all your money on the bed itself.

Filling

 

The filling before mixing. The compost is the rich dark brown. What seems white is in fact the reflective vermiculite.

In my garden, each bed has a Terram, horticultural lining. This matting holds the soil inside the beds, allows good drainage and stops slugs from burrowing into the soil from below.  When I moved one of these beds a week or two ago, I was very pleased to see that slugs had not multiplied underneath the beds.  My guess is that the Terram matting makes the underside relatively uninviting.  It is slightly rough to the touch and may irritate them. If that is the case, then it was a good choice!

Each bed started out with a mix of ⅓ compost, ⅓ vermiculite and ⅓ expanded coir.  As time goes by, this mix has changed.  I'm not re-stocking with vermiculite.  It does have a nasty habit of ending up clinging to lettuce leaves.  Though it is relatively inert, I don't like to find it on the salad plate!  

Every year I have buried half rotted vegetable matter where I want a hungry crop to grow, and I’ve top dressed, composted and mulched! This gradually modifies the soil.  See October Soil Fertility,  Slowly the thickness of soil is increasing. The original mix seemed to be perfect for leaf crops, tomatoes and potatoes, in the first years, but I didn’t have much luck with root crops like carrots, radish and celeriac at first. I think the mix might have been too nourishing.  I now grow these in special locations.

Depth
The soil in rasied beds is rarely more than 30 or perhaps 45cm deep. I maintain that deep beds are not essential, unless you have difficulty in stooping to maintain them. The arguments are complex.  The roots of plants fall into two categories. There are fiberous rooted species, like legumes, where the roots grow out in a maze of fine feeding fingers.  These wide-rooted plants do well in containers.  Tap rooted plants like carrots have a central root that may grow downwards for many feet.  Tap rooted species need depth and even the shorties like radish and beet may not be happy in shallow beds.  Show carrots are often grown in special rasied bins that are over a meter tall.  

Roots grow in response to a search for water as they grow they amass nutrients within their structure which they release to the plant as the water is percolated upwards. In some plants the water seeking roots may be quite different to the feeding roots. in tomatoes fleshy roots may travel several feet to seek water, but a mat of fine surface roots develops around the top of the soil.  This mat absorbs nutrients. If you water plants well they don't need such a large root system.  (thought they might need staking.)

Nutrition seeking roots do not go deep, where soil oxygen becomes scarce.  Roots make use of this oxygen to metabolise nutritients. That is why compacted soil will not produce good crops.   A glance at soil profiles will reveal that the most nutritious soil is rarely 15cm deep.  Even in forests that support large trees and an undercanopy, the topsoil may be less than 50cm deep.

Roots rarely grow down like an inverted branch pattern, the are much more likely to grow outwards.    Thus shallow but wide raised beds allow the plant roots to fan out for nutrition and even six inches of good quality soil may be more that you will find in the wild. 

Soil profile from forest samples taken by University of Michigan

Trellis
The question of the northern most side of the plot is an important one.  Here you can add a trellis, or other means of gaining height.  This can magnificently increase the growing area, and provide wind protection from the north.  Vertical planting will be the subject of a whole article later in the year (probably about the time I start to plant out my climbing courgette.) But for now the important point is not to forget to allow for the extra space that a trellis will require.

Daylesford Organics. Image Daily Mail

First published March 2013, Updated March 2014

 

 

Having a decorative scheme and eating it

 

Planting Plan: Painting by Wendy Shillam Plant list and key at bottom of page

Well, here it is!  The planting scheme for the spring vegetable bed.  I've spent since Christmas humming and haring about what to plant where.  At the weekend I finally made the leap and started planting it up.  As readers will know, I'm basing all my designs this year on a series of paintings.  This bed is (loosely) based on Cy Twombly Primavera.

Cy Twombly Primavera Credit: Tate

My interpretation relies upon the fresh greens of chicory, chervil and pak choi, interspersed with the deep burgundy of poppies, edible pansies and a miniature red rose.  

My sketch shows everything as if it is flowering at the same time.  I know that's a cheat, but never mind!  The really dark purples will come first in the spring-time , then later in the year the pale lilac of the hyssop and the black zucchini will take over.  By autumn the elderberry, in a pot at the back of the arrangement, will have black berries instead of white flowers.  I'm hoping that this will, by then, contrast nicely with the black and white winter bed that I'm planning behind this one.

I'm a great fan of white umbelliferous flowers.  Garden designers seem to love using these in domestic flower borders.  My white umbells come from elder-flowers, dill and chervil. I've also got salad burnet which has a very delicate umbel of pinkinsh red.

Of course the difference between this and any other planting plan is that everything you see can be eaten in one way or another.   The bulk of the edibles will be pak choi and chicory. I've chosen cultivars for their pale leaves.  I'm also plating some good old tom thumb lettuces, so as gaps appear I can re-plant with something else fresh and new.  

I've decided to show the garden in early June for the Chelsea Fringe.  I'm just hoping that everything will look good on the day and that I won't be tempted to eat it all before then. 

Planting Scheme

1. Sambuca Nigris,  common elder in a pot
2. Pak choi, White Petiole
3. Dill
4. Papaver Orientalis, Oriental poppy - deep red
5. Chervil
6. Miniature rose, burgundy
7. Salad burnet
8. Zucchini, Tumbling Black
9. Chicory, Variegata de Castelfranco
10. Pansy, purple
11. Hyssop hedge 150mm high

 

 

August Plant Tarragon

Tarragon is the queen of herbs, and one of thoses that the French refer to as ‘fines’. It is a great mixer on salads or to flavour dishes, but its magic alone is best brought out by flavouring chicken.  Tarragon has a slight aniseed flavour that cuts fatty dishes like eggs and meat.

There is a certain amount of variation in a French chef’s definition of what herbs are fines, but my research has led me to believe that Madame would simply go into her potager to find the freshest green leaves to flavour her food. These are the leaves that do not require long cooking to soften them and do not overpower.  Thyme and basil never seem to feature in the mix.  Chervil, chives, parsley and tarragon all have a long life in the potager, and they all feature regularly in fines herbes mixes recommended by chefs. 

Parsley will generally endure winters. This crop is on its second year outside.

There are two types of tarragon, Russian and French.  Russian tarragon can be grown from seed, but beware, it is not of high culinary value and people report that the leaves taste dubious.  French tarragon is much more difficult to grow, it does not set seed and should be propagated from cuttings.  It is French tarragon that is the real McCoy.

I grow my tarragon in a pot filled with very a sharp, well-draining soil mixture.  It won’t need a lot of nutrients as it is naturally most happy on top of a bare mountain in Alpes Maritimes in the south of France. I figure that a sunny spot on my rooftopvegplot is not so different.  Tarragon needs loads of sun, and sulks in the winter.  I take the pot indoors, giving it the sunniest and most sheltered spot in the greenhouse.

Of the other fines herbs, chervil and parsley grow well, overwintering in the greenhouse, but I find chives fare far better if left to fend for themselves in the ground outside.  I let them die down in the winter and they come back of their own volition come spring.

If I pot up cuttings of French tarragon now and plant seeds of parsley and chervil in early autumn, I know that I can enjoying fines herbes on my salad or adorning an organic egg omelette all year round.   

Fines herbes keep well in pots, under cool protection, during winter

Flowers in the vegplot

Marigold Calendula Officinalis. A brillian plant for attracting pollinators and putting pests off the scent.

With so many vegetables to be grown, potted on, hardened off and generally tended this month, you may wonder why I’m piling more work onto my shoulders by thinking about flowers amongst the vegetables.  But when June, July and August come around, I know that if I haven’t planted a few annuals now, I will regret it.

Background Mizuna left to self seed, foreground a rose flowering in June, to deter aphids. Note: the rose is planted in its own pot. Within a rasied bed, it might become too greedy of nutrients.

Flowers can arrive amongst the vegetables in all sorts of serendipitous ways.  They can be self-sewn, vegetables may go to seed, perennials may naturally bloom, fruit must flower before the fruits are born and of course, you can always sow something. 

Well selected flower cultivars provide good foraging for the bees and other beneficial creatures that we want in our gardens.  At this time of year I’ve left a few flowering Chinese broccoli, which will attract and feed early-bird bees.   The white flowers on tall spikes are not the most glamorous, but they add brightness in dull corners.   In addition Calendula officinalis, common marigolds, are starting to show themselves.  These are plants which naturally self-sow in autumn.  I shall hand-sow a few more deliberately now for a colourful border amongst the onions and garlics.

Herbs are a wonderful addition of flowers to the garden.  This year I have purchased Hyssop officinalis, which according to the Herb Gardener Blog 

Bees love Hyssop and it's also a favourite with butterflies and hummingbirds. As a companion plant, it can help keep a few unsavoury visitors from the garden too. It repels flea beetles and cabbage moths, so keep it around your cabbage crops and grape vines.

I am planning to keep this rangy perennial in check by cutting it back to make a 20 cm hedge.  I'm hoping that this will protect a rather windy bed on the western edge of the garden.   It remains to be seen whether I will get more, or fewer flower spikes that way.  I’m making similar edgings this year around other beds, using rosemary, thyme, chives (which have a pretty pink flower) and parsley.  These will provide perfumes well as flowers in summer. 

Hyssop 'hedge' in the raised bed and freshly trimmed lavender in a pot.

I have also sown a ring of chervil around the Wisteria pot.  It has a long tap root, so will befit from a deep pot, and it will like the slightly shaded shelter of a south-east facing wall.  It needs loads of water, but so does my Wisteria!

 Chervil is said to deter slugs, but don’t hold your breath!  It is however, a lovely herb, being one of the three fines herbes used by the French to dress an omelette. In my view it is an essential culinary staple.  It has delicate serrated leaves and lovely bracts of white umbelliferous flowers, similar to those of dill, fennel or angelica (both of which also adorn any corner of garden with floriferous beauty.)

Companion plants abound in the seed catalogues.  Some that I always use are:

Nasturtium, which has edible leaves, flowers and seeds (they taste like a milder form of caper). Last year they certainly attracted Cabbage white’s, I found a whole colony on one leaf.  Foolishly I didn’t do anything about it, and before you could say nasty-smelly-chemical-insecticide, I was having to strip hundreds of leaves of the nasturtiums, each of which had been nibbled by a caterpillar of Alice in Wonderland proportions.  They can’t half grow and they can’t half shift.  Next year I will be more vigilant.

Red Emperor Nasturtium and a ring of Chervil underplanting the wysteria.

Sweet peas.  I cannot imagine a row of runner beans without sweet peas growing through them.  They attract the bees to the runner bean flower as well as shading and supporting the rather spindly early bean-stalk.  Like all peas they are hungry, but they fix nitrogen, so give back to the veg-plot for next year.

Scented sweet peas and runner beans

Early spring, when every square foot of the garden is not in use is also a good time for flowering bulbs.  I have miniature tulips and hyacinths budding right now.  They hyacinths are nestled comfortably in the garlic bed and the tulips are occupying space that I won’t need until later in May.  Both benefit from being lifted after flowering and stored until autumn next year.  You can leave them to die down in the plot, but I tend to lift them with their leaves still intact and store them outside in a shady spot until the leaves have died down.

During the summer many vegetables will flower beautifully, I have already mentioned the bright red flowers of Red Emperor runner beans but there is also the delicate veined brocade white bells of rocket and frilly yellow and white flowers of the lettuce and Chinese leaves family.  Each time a late flowering of the crop is present, leave it and save the flowers for seed next year.  Easily saved seeds, like mizuna (a serrated Chinese leaf) will soon develop into a special strain fitted perfectly to the conditions in my garden.  But I don’t save the first flower, neither the spindly ones.  If I were to do this, I would be selecting for weaker plants that go to seed too readily!

 

Rocket in flower

In March most hardy annuals can be sewn direct and half-hardy or more delicate ones can be sewn inside and hardened off and planted out in April or May.  For sheer joie de vivre I sow Nigella, poppies, hollyhocks and sunflowers.  The delicate blues and reds of the Nigellas and poppies can be broadcast, and come up where they will.  The climbers live in tall pots close to the garden bench, and provide colour during those arduous summer days when I shall be sitting on a deck chair watching my garden grow!

Ipomoea, morning glory and garden peas.