Wednesday, 5 March 2014

Growing potatoes in a bin bag

There’s no doubt that growing potatoes in the open ground, whether a garden bed or an allotment, takes up a lot of space. And a lot of space is usually something the urban gardener often doesn’t have. 
However, you don’t have to grow them in the open ground at all. You can grow potatoes in a container, ideally a strong sack … or indeed, a bin liner. And right now in March is a good time to start them off.
You might have seen advertisements in the Sunday magazines for special potato sacks, but you don’t need them. A nice strong black binbag will do. Or a compost bag, so long as it has that black lining inside. The black lining is to keep the light out, so that the potatoes inside don’t go green.
Growing in a container
The best type of potatoes for planting in a container are early varieties - those which reach maturity the quickest and are ready for harvesting around 110 days after planting. We successfully raised Lady Christl, Anya and Charlotte potatoes grown in bin bags at the Secret Garden Club. 

Lady Christl potatoes have beautiful, unblemished yellow skins and creamy white flesh. The potato is firm with a delicate buttery flavour and they make a delicious salad. The Anya variety, originally grown for Sainsburys, is a cross between Desiree and Pink Fir Apple, the Desiree side of the family smoothing out the knobbles and bumps that are characteristic of Pink Fir Apples, leaving Anya relatively smoother skinned and nutty flavoured. Charlottes are a classic salad potato with a waxy texture.

Freshly dug Lady Christl potatoes.
When you buy your seed potatoes, it's a good idea to let them develop little shoots, called 'chits', before you plant them in your bin bag. The potatoes will chit, ie, send out these little shoots, if they are kept in a light cool place. Note, a light cool place. If you want to store potatoes for eating, keep them in the dark. If you want to store them before planting, keep them in the light.
It’s not essential to chit potatoes but it does get them off to a good head start in the ground. It also helps you to plant them the right way up - the shoots should be pointing up towards the sky.
Each compost bag will take three seed potatoes, seed potatoes being the starter spuds which will grow into new potato plants. From each seed potato you should be able to harvest around eight or nine eating potatoes.
While growing potatoes in a container obviously takes up less space than raising them in the open ground, there are other advantages as well:
  • It's less hard work – no digging;
  • Portability 1 – if you get a bad weather warning (eg, frost) when the plants are young and tender, you can move them indoors/under cover;
  • Portability 2 – you can place the bags more or less wherever you like.
  • There is less risk of disease – your purpose-bought compost shouldn’t be harbouring blight spores, eelworms or any other nasties;
  • You don’t need to dig out the potatoes with a fork or spade, so there is little or no chance of damaging the spuds when harvesting;
  • Gardeners often miss very small potatoes and leave them in the ground over the autumn and winter. By growing them in a bag you can ensure you harvest your entire crop.
How to plant potatoes in a bag
1) The first thing to do is to put about three inches of compost in the bottom of the bag, spread evenly. Make it easier for yourself by rolling the sides of the bag down so that your bag is about six inches tall. You’ll want the sides rolled down anyway after you plant the potatoes – if you keep the bags at full height your potatoes will never see the sun and they won’t grow.
2) Next you want to take a sharpened pencil or sharp stick and make some drainage holes in the bottom of your potato bag. This is very important – you do not want waterlogged potatoes.  They will rot, and rotten potatoes stink.
So, make about 5-6 drainage holes at the foot of each bag.
3) Now place three potatoes into the bag. Space them out evenly.
Always use seed potatoes, ie, bought from a nursery or garden centre specifically for growing. Seed potatoes should be guaranteed free from viruses, which culinary potatoes won’t be. Potatoes in the shops may have been sprayed with a shoot suppressant.
Potatoes in the shops may not have been grown in the UK and so may not be well adapted to grow here. Many, if not most, of the seed potatoes grown in the UK come from Scotland and are bred to grow well in our conditions.
4) The potatoes should go into the sack with the chits uppermost.
Yup, see them little roots...they go upwards, those will be the shoots growing above the ground to grab some sunlight for the plant.
You can grow potatoes without chitting them first but they take longer to get going. You can also cut seed potatoes up into divisions each with its own little chit and plant them individually, but you do get bigger plants and more potatoes by planting the whole spud, chits and all.
5) Once the potatoes are in, cover them with more compost: aim to have a layer of compost about 2-3 inches thick over the chits.
6) Finally, water them lightly. They don’t need to be soaked. Check that water is seeping out of the drainage holes.
7) Put the potato bag outside somewhere light and somewhere reasonably sheltered.
You’ll need to bring the bag inside if a frost is forecast. We may have had a very mild winter this year but we could easily still get a cold snap in March in London; much more unusual in April, although we’ve had late frosts in each of the last two years.
8) After about 2-3 weeks you’ll see the dark green leaves poking up through the soil surface. Once the leaves are about 3-4 inches above the surface of the compost, add more compost to the bag, until the green tops are only just visible above the soil surface.
You’ll probably need to starting unroll the sides to accommodate the new compost as well. This is an ongoing process. Every time the plant grows so that you have about 3-4 inches of stem and leaves above the surface, unroll the sides a little more and add more compost.
If it rains a couple of times a week, you probably won’t need to water them. But do check your compost: if it’s very dry, then water it. Make sure any excess water is running out through those drainage holes. If it rains a lot and you put your hand in and the compost is sodden, move the bag under cover for a few days to let it dry out a bit.
The potatoes will take about three and a half months to reach maturity and edible develop tubers.
So, in about mid-June, you can put on a pair of gloves and stick your hand into the compost. If the lumps are still tiny, leave them longer. If you can feel that you have big potatoes, start harvesting.
Other signs are also useful: once the potato plant is flowering you can try digging up some spuds, or your deep green foliage might start turning yellowy and begin to wilt.
The best way to harvest here is simply to up-end the bag on to a surface and pick out the potatoes. Put the rest of the plant on the compost heap and spread the compost on your garden beds.
Charlotte potatoes spilling over the top of their bin bags.

Thursday, 30 January 2014

Under the gooseberry bush

Ripe dessert gooseberries (Gooseberry 'Pax') ready for harvest.
We've planted three gooseberry bushes in the Secret Garden this winter, in a sunny sheltered bed down by the summerhouse. With the fig tree establishing itself against the summerhouse walls, it's a good spot for soft fruit: south-west facing, out of the main winds, and not exposed so it won't get the worst of the frosts.

We've planted a cooking variety, Invicta, which will ripen to a bright green and which are superb in tarts and crumbles. Gooseberries also make a remarkably good curd - see here for MsMarmiteLover's gooseberry curd recipe.

Some dessert varieties will ripen to a golden, or maroon colour, are much sweeter when ready to be picked and can be eaten straight from the bush. Cooking gooseberries are much tarter, even when ripe. They generally stay green (but then, so do some sweet varieties).

Gooseberry plants have vicious thorns and Invicta are also known for being particularly thorny - we'll wear gloves when picking, pruning, or hand-weeding them.

Gooseberries are pretty forgiving where soil is concerned - you can plant them in clay, or poor soil, so long as it is reasonably well-drained, but they do like the sun. Often you will buy them as bare-rooted, pruned, plants in winter - the best time to plant them is November/December, or early spring. Don't try to plant out your new gooseberries when the ground is frozen, or waterlogged. If your plants are delivered and the conditions aren't right, just pot them up in a pot big enough to take the roots comfortably and keep the pot somewhere sheltered and frost-free until they can go in the open ground.
Gooseberries potted up to be planted out when the ground is
neither waterlogged nor frosted.

To plant out, soak your bare-rooted plants for about half an hour beforehand in a bucket of water. (If your plants are potted up, water them well before planting out. Dig out a squarish hole where you want the gooseberries to go, and fork in some organic matter. Water thoroughly. Place the gooseberry plant gently in the hole and spread the roots out. The plant should sit comfortably so that the soil surface is just above the roots at the base of the stem - there will be a mark on the stem showing the original planting depth, and you should plant to the same level as this again. Fill the hole again with the displaced soil, firming it lightly as you go and holding the plant steady so that it remains upright. Mulch with some more organic matter and water again.
Gooseberries 'Invicta' planted out, with a little extra organic mulch around the base of each plant. 

If you have finches in your neighbourhood you might consider covering your trees with a net in winter: finches love the embryonic gooseberry buds as they develop. Otherwise, leave your bushes to settle in, watering them regularly until they are established.

Gooseberries fruit on two year old wood, so don't worry too much if you don't get a crop in your first year. The plants will flower in May here in London, although the flowers on many varieties are small and easily missed. The fruit will start to ripen in July, and now you should definitely consider a net unless you want the birds to help themselves to your crop.
Gooseberries ripening under a net to protect them from birds.

In a really good year when it looks as though you're going to have a glut, you can thin the unripe fruits out in May/June, leaving half to two-thirds of the crop to ripen on. If you have a dessert variety, the unripe fruits can be prepared as though they were cooking gooseberries, with the promise of the sweeter ripe fruit still to come. You get the best of both worlds.

Newly planted out in the open ground.

Thursday, 23 January 2014

Rhubarb - may the force be with us


Following our success with forcing chicory, we’ve turned our attention to our rhubarb crowns. Forcing rhubarb is a notable tradition in the UK, providing bright pink, tender stems to harvest at a time when there is little else to be dug out of the ground.

You may have heard of the ‘rhubarb triangle’ – not a place where rhubarb mysteriously vanishes, but rather an area in West Yorkshire bordered by Wakefield, Rothwell and Morley, where rhubarb is grown in special darkened, warmed sheds and forced to produce early stems between January and March for UK shops. Lit only by candlelight, the sheds house 1000s of rhubarb plants which send out long slender shoots in search of light. You can even take a Yorkshire rhubarb triangle tour, during which you can even hear the fast-growing forced plants popping if you listen closely. Forced rhubarb from this area of Yorkshire has been granted Protected Designation of Origin (PDO) status by the European Commission.

With our two young rhubarb plants, we won’t be forcing on quite the same scale, but the same principles apply. As with chicory, the process deprives the growing plants of all light. The resulting stems (rhubarb) or leaves (chicory) are pale and more tender, more delicately flavoured than those grown in the tough outdoors. The darkened plants will also grow faster, desperately hunting for light in order to photosynthesise and convert sunlight to energy.



The best time to start forcing rhubarb is when you can just see the first signs of new growth at the turn of the year. Up-end a large dark-coloured pot, or bucket, one that is big enough to accommodate the growing stems, over the whole rhubarb crown. Pin it down into the soil with pegs, so that a) there’s no danger of the bucket blowing away in a winter storm, or b) no light gets in between the edge of the bucket and the soil. Any drainage holes in the bottom of the pot must be blocked off to stop even those pinpricks of light from getting in. I usually cover them with stones or concrete slabs, which has the dual effect of blocking light and again weighting the pot down so it doesn’t blow away.




Try to do this during a spell of dryish weather so that the embryonic plant isn’t wet when you cover it with the pot. Also don’t cover the rhubarb when the ground is frozen or the covered plant will remain too cold. It’s also a good idea to give the plant a quick onceover for slugs, woodlice and the like.

You can now leave nature to take its course. Check the plant every couple of weeks for growth and in 4-6 weeks you should be cutting your own forced rhubarb. The forced stems are generally less fibrous and slimmer than ‘normal’ rhubarb stalks, and also a bright pink – the colour of Pepto-Bismol rather than the darker crimson of stems grown outside in summer.

The incipient leaves should be removed as these, like their outdoor grown counterparts, are poisonous. Then the forced stems can be used in cooking just as you would for any rhubarb – poached, in a fool, or as a savoury accompaniment to meat or fish. Or treat yourself to a classic rhubarb crumble with MsMarmiteLover's recipe










Wednesday, 15 January 2014

Secret Garden Club in winter


It may be the middle of winter but there is plenty of life and colour in the Secret Garden, helped by the relatively mild weather (if not the persistent rain).

Clockwise from top left: the camellia tree is in bud, ready to burst into bright red flowers in February; Clematis sieboldii flowers are determined to continue throughout the winter; the cavolo nero (Tuscan kale) is thriving; winter jasmine provides a welcome splash of yellow against the ivy-clad fence; the oriental salad plant mizuna provides leaves for winter salads; violas brighten up the patio in their pots.

Elsewhere, we have primroses, spring bulbs are pushing spiky leaves above ground in every bed, and seedling lettuces and carrots are ready to put on growth as soon as the weather gets warmer to provide us with early crops.

Monday, 16 December 2013

Chicory tips - forcing chicory for winter salads



Chicory is a dandelion-like plant which grows thick strong leaves. These are tough and bitter to eat, but at some stage of human evolution, people discovered that if the plants were made to grow in the dark, they would send out tender, crunchy, sweeter shoots that were much nicer to eat. These pale, yellow tipped shoots are called chicons - it's almost worth growing them for the lovely name alone.

Hence, forcing. We don't only force chicory. Rhubarb is forced to produce sweet tender stalks in February/March, a month or two before the unforced plants are ready naturally. Much of the UK’s forced rhubarb is grown in West Yorkshire around Wakefield, an area known as the 'rhubarb triangle', where row after row of blacked-out sheds are lit only by candlelight. You can even hear the stalks popping as they rush to send up shoots in search of light.

The French frisee, the crunchy lettuce with feathery leaves, is typically forced, by having a bucket set over the centre of the plant while growing, to produce a heart of white crunchy leaves. Frisee is related to chicory and here the forcing has the same effect: the white shoots are much more tender than the naturally grown green leaves.

We’ve been forcing chicory here in the Secret Garden Club for the first time this year.

With rhubarb and chicory, the plant must be well established before you try to force it. It’s no good planting a seed or seedling and then plunging it into the dark. The plant must have developed a good root system with stored nutrients. So you sow your chicory seeds in spring as normal, and raise the plant out in the open throughout the summer.

Three weeks ago, we dug up nine chicory plants like these and trimmed off all the existing leaves, to leave just the taproot. We replanted these roots in damp compost in pots, three chicory roots to a 25cm pot, and covered each pot with an upturned black bucket. Then just to make sure no light crept in, we covered the pots with a black bin liner for good measure.

In January we’ll be doing something very similar with our rhubarb and forcing that to produce early, bright pink, tender stalks. They have a more delicate taste compared to the robust stems which grow out in the open and which we’ll start harvesting in April.

Top tips for growing chicory for forcing
  •      Plant chicory in spring. You can grow in pots or troughs, or in the open ground. We’ve done both, using a discarded recycling box (recycling it, in fact) as a trough. The plants in the beds outside generally grew bigger and stronger taproots.
  •      The chicory plants look remarkably like dandelions when they’re growing. Don’t weed any by mistake.
Top left: choose a chicory plant with a nice fat base. Top right: Trim the
roots if they are particularly long. Middle left: drop the chicory root into
a pot filled with compost. Middle right: firm the soil around the
chicory. Bottom left: cut off the leaves at the top of the root. Bottom
right: three trimmed roots ready to be forced in the dark.

  •      You don’t have to force all your chicory at once. Look for those with a taproot about 2cms or more across.
  •      Loosen the root and carefully lift from the soil. Trim the roots if they are very long.
  •      Cut off the leaves about 1-2cms above the root.
  •      Replant in a pot in damp compost. You can replant 3-4 roots in a 30cm pot.
  •      Cover the pot with a bucket or something that will exclude all light. It must be completely dark.
  •      Place the pot somewhere frost-free and relatively warm – ideally within 12-16 degrees Celsius. It’s good idea to put it somewhere dark like a cupboard just to ensure the roots aren’t exposed to light.
  •      Apart from checking the compost stays moist, leave alone for 3-4 weeks, when the chicons should have formed.
Chicons beginning to grow after a week in darkness.

Three weeks after the chicory plants were transplanted,
trimmed and repotted, we removed the black cover to find
chicons ready to be harvested.
For other accounts of forcing chicory and how to do it, see this post on GrowVeg.com, or here on My Tiny Plot. There is also an account of forcing red Rossa di Treviso chicory on Freshly Picked.


Friday, 29 November 2013

Hydroponics - growing without soil


Growing plants hydroponically, or without soil, is a clean, and resource-efficient way to successfully raise a variety of produce. While it has only become an established way to grow vegetables on a commercial scale in recent years, it's not a particularly new invention. The Hanging Gardens of Babylon are reputed to have used hydroponic growing techniques as were the floating gardens of Aztec Mexico. It's been used on Pacific Islands with no topsoil .  Closer to home, the philosopher/scientist and parliamentarian Francis Bacon – the one who some people suppose may have written some of the plays attributed to Shakespeare – wrote about soilless planting, and called it 'water culture'.


Conventionally, plants are grown in soil, typically made up of minute rock particles, organic matter (material which was once living, now decayed) and water. The chemical nutrients in soil, dissolved in the water, feed the plants and enable them to grow. The purpose of the soil itself, rather than the water in the soil, is to act as an anchor for the plant's roots, keeping it stable. So long as you provide the same liquid nutrients in such a way that the plant's roots can take them up, and you also give your plants something to hold the roots in, you don’t need the soil itself.


There are advantages to eliminating soil. Soil is messy stuff for one thing, and for another there is always an element of guesswork in using soil. It's difficult to know precisely, how rich, how chemically balanced, how fertile a soil is. If you have no garden, or are restricted to a patio or courtyard, or maybe have no outdoor space at all, you may not want to be lugging bags of compost through the house. Soil can also be contaminated, by toxic metals, or more mundanely, by pests or harmful fungi living in it. In this last case, you may not wish to grow edible foods in such an environment.


In a hydroponic set-up, you need a container for your plants, plus a growing medium which will be an inert material such as Perlite, Vermiculite, or rockwool (available from most garden centres), all three of which are rock-based, and highly water-absorbent. You can float your roots in water so long as the main stem has a collar, or block, to stabilise the plant. You will need to provide your plants with warmth, light and nutrients.


If you look around on the Internet you'll find off-puttingly long lists of technical equipment required for a hydroponic set-up: pumps, filters, hoses, lights, heat lamps, etc. You would be forgiven for thinking it's less like growing plants and more like a laboratory experiment.


However, much of this expensive and hi-tech kit is needed for hydroponic growing on an industrial or commercial scale. To successfully grow salad leaves an herbs on a windowsill, some pots, water and a soil-less growing medium is all you really need. And your liquid nutrients, of course. I tend to stick my hydroponic pots in a south-facing window and let them make the most of the natural warmth and light from that, but then I'm growing mostly herbs and salads which are less fussy than some plants.


Many of the salad leaves sold in supermarkets are grown hydroponically, as are what they call salad vegetables: tomatoes, peppers and cucumbers. If you’ve ever wondered how tomatoes can be labelled as UK grown and sold at this time of year, it’s because they are grown indoors, hydroponically. You may have heard of Thanet Earth, which is a site of four massive greenhouses covering over 200 acres, which grows solely tomatoes, cucumbers and peppers, all grown without soil, and all for distribution into supermarkets in the south-east. For Thanet Earth, being able to precisely control the environment means they can harvest tomatoes 52 weeks a year, cucumbers from February to November, and peppers from March to November. With no soil-borne diseases to worry about, Thanet Earth aims to use no pesticides at all – they do use biological controls, ie, introducing predators to deal with any pests.


Hydroponic cultivation has its opponents. The development of Thanet Earth was covered in the Daily Mail and included a quote from Jeanette Longfield of the food campaign group Sustain, who said: 'What are they going to taste like if they are grown in water rather than soil? … This is about producing bland food’.


The argument here is about what the French call 'terroir', when referring to growing grapes for wine: the complete environment that the plants are grown in, including the microclimate, the soil, and terrain. If the idea of terroir can give grapes their own individual characteristics, then logically it can also apply to fruit and veg. That while we calibrate liquid nutrient solutions and precisely control the climate (heat, light and water) for hydroponic crops, there may be trace elements or micro-minerals present in soil that we are overlooking in the hydroponic environment. I don’t know the definitive answer to the taste question. If you follow the terroir argument through, then a hydroponic crop should be very 'pure' tasting, with little or no deviation from one growing location to another. And there should be no bad years.



Pak choi plants growing in a hydroponic trough on the windowsill.

In this age too where organic growing is seen as 'better' than intensive farming - and hydroponic growing is pretty intensive, hydroponic cultivation can be seen as a step backwards.


What an organic philosophy and hydroponic growing have in common is the desire for sustainability. Both methods are far less fuel-intensive than using manufactured fertilisers. Organic systems aim to reduce soil erosion and exhaustion with the addition of organic matter; in many hydroponic systems, the growing medium can be reused many times. For example, perlite, the rock granules which are often used to anchor the roots, can be sterilised in a microwave and then used again for the next batch of hydroponically-grown seedlings. Thanet Earth exports electricity to the neighbouring area and recycles all its water. The micro-management that delivers precisely the nutrients needed to the growing plants also means there is far less waste.


Hydroponics - the good news ...

+ Sustainable
+ Efficient use of resources - less waste
+ Takes up relatively little space, with high yields
+ Versatile – does not need fertile soil, can be grown anywhere
+ Cleaner to maintain

... and the not-so-good

- Cannot be called organic
- Lot of management required to get the balance right
- Leaching if not managed properly
- Only suitable for some plants
- Concerns that soil-grown vegetable taste better

Hydroponic growing is ideal if you don’t have a garden, or you are restricted to pot-growing. The lack of soil makes it less messy for a start; the use of a precise set of nutrients administered at regular intervals takes a lot of the guesswork out of growing.


Where to buy

We used a simple base kit, costing £32.50 from The Achiltibuie Garden. Based in the north-west highlands of Scotland, this company specialises in developing hydroponic growing systems for domestic use. Many of their systems are modular, so that you can add extra units to the base kit if your needs increase. This windowsill kit shown below, is good for raising salad cut-and-come-again leaves and herbs.

The acorn pot in the top photo is suitable for growing chillies and also tomatoes, and also comes from the Achiltibuie Garden, costing £45.00 for a pack of three pots, plus a Perlite-based growing medium, mini-propagator, sample seeds and a generous supply of liquid nutrients.

Closer to the Secret Garden Club is Growell Hydroponics in Neasden, just off the North Circular in Brent Park and with branches throughout England, in Merton, south London, Birmingham, Bristol and Sheffield, among other places. They sell everything from nutrient mixes to complete irrigation, lighting and tenting systems for indoor growing.

Sunday, 17 November 2013

Saving herb seeds


Seeds from the Secret Garden's fennel plant against the sky.

The fennel plant in the Secret Garden is now over seven feet tall, throwing out aromatic feathery leaves, delicate flowerheads which then produce a multitude of pungent fennel seeds. This is a fennel plant (Foeniculum vulgare), grown as a herb rather than the variety grown for its bulbous root (Florence fennel or Foeniculum vulgare "Azoricum"). The leaf fronds are used for flavouring fish and salads, the flowers in pickles, and the seeds in spiced foods, stuffings, and sauces.

Herb fennel is a perennial plant. These impressive high stems will die back over the winter, but you'll usually see bushy feathery regrowth at the base of the main stalks starting in autumn which will come back strongly in spring. It is happiest in a light, well-drained soil in a sunny sheltered site.

Having successfully raised your herb plants they will eventually set seed if you leave the flowerheads on the plant.  Herbs like coriander, dill, lovage and fennel have edible seeds as well as leaves. In using the seed in the kitchen as well as the leaves - and also the flowers, see our post here - you will be getting maximum value from your plants. The seeds from your own herbs will also have an unmatched freshness and concentration of flavour.

Even if you don’t eat them, you can save the seeds to grow next year. This is one way to ensure that over the generations you will raise plants which is perfectly adapted for your conditions. 

Let the plant grow and flower, after which it will set seed. Cut the seedheads before they fall to the ground. You might want to put the whole seedhead in a paper bag and snip the stem to ensure no seed is wasted. 

Next, remove the chaff – the bits of stalk and seedcase. Put the seed in a jar and seal. Label it carefully. 

Store seed somewhere cool, dark and dry, and, for culinary use, try to eat them within three months. If you're saving the seed to sow again next year, keep them in a paper bag or envelope (not plastic or polythene), rather than  a jar, again somewhere cool and dark.

For detailed advice on saving seeds for a number of vegetable plants, the best place I've found on the web is Real Seeds which has detailed and authoritative advice.