Growing Tomatoes – ‘Blossom End Rot’

A common problem that has been affecting this year’s crop of tomatoes (for allotmenteers who have greenhouses – or those, like me, who are experimenting with outdoor varieties) is ‘blossom-end rot’.

What does this look like? – The condition can easily be recognised by the base of the fruit turning black as it matures and ripens.

What are the causes? It is important to realise this is not a bacterial disease nor is it caused by pests. It is actually a calcium deficiency in the plant. (Calcium is necessary for forming the skin of the fruit, and the blemishes occur when the plant is starved of calcium as the fruit is developing).

Why does it occur?  Whilst it is possible that the lack of calcium could be a problem with your compost or insufficient feed applied to the plants at the right time, it is not difficult to work out why this condition is more prevalent this year. By far the most likely cause is erratic watering as the fruit develops – often unavoidable in the kind of drought conditions we have been experiencing. If the plant is allowed to dry out, it cannot absorb the calcium it needs. Be careful, though – over zealous watering can also have the same effect.

What can you do? Not much, I’m afraid – other than adjusting the watering. The good news is that the condition doesn’t affect the taste of the rest of the fruit – just cut off the affected parts and enjoy the remainder of your labours. The other upside is that it doesn’t necessarily mean that later fruit on the plant will be affected. If the plant gets the right amount of water, fruit now forming could well be fine.

How to avoid the problem in the future? Good quality compost will help but, as I’ve already indicated, not allowing the plant to dry out is the surest way to avoid the problem. Other things that might assist:

  • Choose a variety that is resistant to the condition
  • Plant the tomatoes out at the right time – planting too early when the soil is still cold can affect root growth which will exacerbate the problem
  • Mulch the soil at the base of the plants to help retain moisture as the plants grow
  • Feed the growing plants with a product designed for tomatoes – and resist the temptation to overfeed (this can be as bad as under-feeding!)
  • Add crushed eggshells (high in calcium content) to your compost – most soil will not be short of calcium – but this won’t do any harm and could help if the condition persists

Hopefully, though, next year will not see such prolonged spells of high temperatures – with apologies to those who like it that hot!


Sowing Kohlrabi – June/July


If you have started to create space from early crops in your allotment and are looking for something a bit different to grow as a late summer/autumn crop, why not try Kohlrabi? This tasty and nutritious crop comes in white, green and purple varieties – but, for late sowing, it is better to use the purple variety which can even be sown into August.

Create a firm seed bed in any reasonably light, fertile, free draining soil. Work in some general purpose compost or a handful of a suitable fertiliser. (The soil doesn’t have to be that deep as the bit we are interested in is the swollen stem growing above ground). Normally, the germination rate is high even in colder parts so sow thinly. Create a groove 1-2cm deep and sow one seed every 5cm (2″). Allow 25cm (10″) between rows. Seedlings should appear after about 10 days. Thin out to one plant every 25cm.

Kohlrabi is a brassica so is subject to the normal pests you might expect – particularly the cabbage white! But it is probably slightly more resistant and trouble-free than most other varieties in this family. They will need watering though – probably a little more than other plants.

Harvest the Kohlrabi when the swollen, round stem is about the size of a tennis ball. The leaves can be eaten as you might use Kale – but, beware, it is a strong flavour. The best bit is the swollen stem. Simply cut the top and roots off, peel the outer layer and either grate into a salad or into a slaw or cut into chunks and steam until tender (6-8 minutes). A favourite of mine is to then puree the steamed Kohlrabi – Yum.



Sowing swedes – May/June

Swedes (Swedish Turnips) are a really great vegetable. Mashed with lashings of butter and a generous dusting of black pepper – it doesn’t get much better that that! So how about cultivation?

Firstly, let’s deal with the soil and position. Swedes will not tolerate waterlogged soil; it needs to be free-draining. So, if your are down the ‘wet’ end of the allotment site, consider a raised bed or grow them on ‘ridges’ in the soil. Swedes need alkaline soil – so they will do well in the clay soil of the East Riding. Work the soil well and dig in a lot of well rotted compost to improve drainage. A light dusting of general purpose fertiliser two weeks before sowing will also help get the crop off to a good start. Choose a nice sunny spot but remember, the young plants will also benefit from a bit of shelter if we get more of the recent cold winds coming off the North Sea.

Sowing direct

The best time to sow swede is mid-May to mid-June but, since it’s a winter crop, delaying until July won’t matter too much. You can sow direct in rows about 35cm (14″) apart. Sow the seeds (which are quite small) thinly and cover with about 1 cm (1/2″) of soil. As the seedlings emerge thin out to approximately 25cm (10″) apart. Slugs and birds will attack the young plants so you will need to take precautions and net the plants initially.

Sowing in modular trays

Alternatively, you can sow the seeds in modular trays. Fill the tray with compost and put two seeds in each module, again about 1 cm deep. Cover the seeds over, water, and keep the compost moist (but not overwatered) during germination. Plant them out when two proper leaves have formed.

Protection from pests

In addition to slugs, swedes can be susceptible to cabbage root fly and flea beetle – remember they are brassicas! Netting the plants with micro-mesh or using horticultural fleece until the plants are well established should avoid the problem as well as keeping the pigeons at bay.

Swedes will take 5 to 6 months to reach maturity. So some patience is required. But when you add a good dollop of mashed swede to your plate on a cold November or December day, you’ll be glad you stuck to the task.

Sowing beetroot – April/May

You can grow beetroot by sowing directly into well prepared beds, but it is also possible to grow this crop by starting the seed in trays transplanting to their final position after about 4 weeks. The advantage of this approach is that it gives the young seedlings protection from the weather and also birds who will find the young plants are quite a tasty treat. (Young beetroot leaves can be harvested and eaten like spinach).

Beetroots grow best in loose fertile soil which has had a lot of organic matter dug in – but avoid beds where you have recently incorporated manure as this can cause problems with the roots. Beetroot prefers free-draining soil, so planting in raised beds will be better if the soil is heavy and prone to becoming waterlogged.

Beetroot seeds come in ‘clusters’. So each ‘seed’ will actually produce three or four seedlings which you need to thin out after germination.

Sowing seeds for transplanting later…

If you decide to go this route, plant the seeds in modular trays using a seed compost which will be finer and lower in nutrients than a multi-purpose compost. Fill the tray with compost and tap it to let the compost settle rather than pressing it down. Make a hole approximately 2.5 cm deep and drop one seed into each cell. Then cover the seeds with another thin layer of compost. Gently water the seeds in, but avoid overwatering. Keep the compost moist. As the seedlings emerge, select the strongest seedling and remove the others by snipping them out (rather than pulling them which might disturb the roots of the stronger seedling). The young plants should be ready for planting out after 4 weeks. Plant the young beetroots 10 cm apart in rows 20cm apart and water well after planting.

Sowing Direct

Work the soil until you have a fine, granular consistency. Then rake the bed level  and form a trench about 2.5 cm (1″) deep with the edge of a hoe or a trowel. Plant the seeds about 10cm (4″) apart. Space rows about 20cm (8″) apart. Cover the seeds over with soil and water well. As the seedlings emerge remove the weakest and thin out to one plant every 10cm.

Planting out broad beans – April

If you sowed your broad beans in pots earlier in the year, they will be ready for planting out in April (maybe the last week in March if the weather is good!).

The generally accepted advice is plant them in double rows allowing 20cm-25cm between plants and 30cm or so between the double rows to allow access. If planting in a raised bed where you don’t need to walk between rows, then you might consider diagonal rows 20cm apart and 20cm between plants. (There is method in this approach which I will explain later).

Broad beans are amongst the most resilient of legumes and will tolerate low temperatures, but you will need to cover them with fleece if frosts are still likely. (I’ve got a micromesh frame that fits over the raised bed with a removable top cover which also protects my plants from other hazards such as pigeons in the early stages of growth).

Depending on the variety, the plants grow to a height of around 1.2m and will need some form of support. But unlike peas and runner beans, broad bean plants aren’t climbers so using cane ‘wigwams’ or a climbing net won’t work.

Using posts at the corners of the bed and enclosing the plants in a string framework will do the trick although a better method of supporting the growing plants is to use canes and then form a lattice work with string at different heights between the canes. Here’s where diagonal rows can help. Using canes around the bed and spaced along the diagonals, a criss-cross string lattice is easy to build allowing the plants to grow up through the ‘cells’ of the lattice.

Growing horseradish in containers – March

For many, horseradish sauce is an essential accompaniment to Roast Beef although, personally, I prefer a good dollop of mustard. I do, however, like horseradish sauce served with smoked mackerel or trout. And growing your own horseradish is remarkably simple. It is a hardy perennial that produces a mass of leaf growth, although the bit we are interested in is its root. The plants are very tough, will survive very low temperatures and have very few problems with pests or diseases.

Since the plants are invasive and can be difficult to get rid of once established, it is best grown in a container, raised bed or large pot. You can grow it from seed but it is easier to buy pieces of root (thongs) for planting (or find someone else on the allotments with some you can scrounge). To plant, fill the container with general purpose compost and the make holes with a dibber deep enough to drop the roots in leaving then about 2 inches (5cm) from the surface. Cover the roots and firm down. And really that’s about it, apart from watering during the growing season to prevent the foliage from slumping.

To Harvest
Cool conditions cause the roots to generate the chemicals that give horseradish its fiery taste, so it’s best to wait until October or November to harvest the first roots. Use a fork to loosen the soil. Follow the main tap root to work out in which direction it goes and then locate a couple of the thicker roots (about finger’s thickness) and it should be possible to break these off
Be warned though, young plants may not carry the same strong taste of slightly older plants.
There are many recipes online to make the sauce – Try the BBC Food site for a good one!

Preparing to plant potatoes – March

Really, the hard work for planting and growing potatoes is done in November or December when the soil in your chosen bed needs to be dug, all weeds removed and plenty of well rotted organic matter worked into the soil. This allows the soil to settle and, also, allows the frost to get at heavy clay soil and help break it up. You should choose an open sunny position, avoiding beds where potatoes have been grown in the previous two years. Then, in March, as soon as the weather allows it (and for those of us down the ‘wet’ end of the allotments – as soon as the soil is dry enough), the second stage of preparation begins. Fork the soil, turning it over and removing any residual weed roots and returning weeds from the bed.
Get your seed potatoes a few weeks in advance of planting as it is beneficial, particularly for early potatoes, to ‘chit’ them before planting. ‘Chitting’ means allowing the shoots to form on the seed potato, and allowing these ‘chits’ to develop before planting will encourage strong growth once they are in the ground.

To ‘chit’ your potatoes, the easiest way is to use empty egg trays or cartons. Set the potatoes out on the trays. If early shoots are already forming, you will notice they are normally strongest at one end of the potato (referred to as the ‘rose’ end). This end should be uppermost when placing in the trays. Place the trays in a reasonably warm, light location to start the sprouting process. About 8 to 10 degrees C should be fine but ensure you protect the seed potatoes from frost. Once 2 or 3 strong shoots or ‘chits’ have formed, they are ready for planting.

In the case of Wilberfoss allotments, if your plot has good drainage, then you should be able to get your ‘first early’ potatoes in the ground toward the end of March. But if the soil is still waterlogged then you may have to delay planting until April.

Sowing broad beans in pots – February

Although broad beans can be sown directly into the ground in late Autumn (last week of October or early November) this is not ideal in colder areas, as they may need protection over winter, or where the soil is waterlogged – which is a problem many of us face in the heavy clay soil in the Vale of York. One alternative, particularly suited to wetter soil, is to sow the seed in pots under glass in late February for planting out the following month. Once sown, the pots need cool (but not freezing) conditions for the seeds to germinate. If the seeds are grown on in a warmer location (such as indoors) they will become ‘leggy’ and will be difficult to plant out. So a cold frame or unheated greenhouse is ideal.

Use 7cm/3-inch pots filled with a general purpose compost. It is a good idea to stand the pots in shallow water for half an hour before planting. The germination rate for broad beans is high so one seed per pot should be sufficient. Make a hole 4cm (1 1/2″) and drop the broad bean seed in.

It doesn’t matter much which way up the seed is planted. Fill the hole with compost and pat down. Don’t forget to mark your pots – let’s be honest, most of us have planted seeds and then got our pots mixed up at some point! The ideal temperature for germination is around 12 C but anything above 7 C will give good results.

Once the seedlings appear, move the pots to a position where they will get plenty of light. Seeds planted in the last week of February should be ready for planting out on the allotment in the last week of March.

Good luck – broad beans eaten young and tender are really delicious!

The basics of crop rotation

What is crop rotation?
Put simply, it is growing specific groups of vegetables on a different part of the allotment each year.
Why is it important?
Rotating the crops helps reduce a build-up of crop-specific pests and diseases plus, since different crops take different nutrients from the soil, you are avoiding the risk of particular soil deficiencies. Some crops even put back nutrients into the soil that are helpful to other crop varieties. So crop rotation helps balance the nutrients in the soil.
Do all crops need rotating?
Short answer – No. Perennial vegetables (such as rhubarb and asparagus) are fine to leave where they are each year. Certain annual crops such courgettes, pumpkins, squashes, marrows and cucumbers can be grown where convenient. So too French and runner beans, sweetcorn and lettuces. (But it is still best to avoid growing each too often in the same place).
How do you go about rotation?
Whilst we will give examples in later posts on this site, the principles are simple. There are five main groups of vegetables:
1. Legumes: Peas and broad beans (French and runner beans suffer from fewer soil problems and, as explained earlier, don’t need rotation)
2. Brassicas: Brussels sprouts, cabbage, cauliflower, kale, kohl-rabi, oriental greens, radish, swede and turnips
3. Onions: Onion, garlic, shallots, leeks
4. Potato Family: Potatoes and tomatoes
5. Root vegetables: Parsnips, carrots, beetroot, celeriac, celery and fennel (NOTE: swedes and turnips are brassicas)

So, to run a 4-year rotation, divide out four roughly equal-sized plots (A,B,C,D) and then choose your rotation plan. e.g.

So potatoes are grown in Plot A in year 1, in Plot B in year 2. Plot C in year 3 and Plot D in year 4. Onions and Root Vegetables are grown in plot B in year 1, in Plot C in year 2 and so on…

Effective rotation will help keep your plants nourished, healthy and free from pests.

Planting new rhubarb crowns – February

February is a month of preparation. There is a lot to do and a great deal of anticipation focused on the coming year. In one of last month’s posts, we talked about forcing rhubarb. Well February is the month you can add to your stock of rhubarb by planting new crowns, and maybe try some new varieties. Growing rhubarb is remarkably easy as, once established, it needs little maintenance and will produce a great crop year after year in the same location without too many problems.

You need a moist, but well-drained location – so if drainage is a problem, consider a raised bed, as the crowns will rot if waterlogged. Although rhubarb prefers a sunny location, it will grow quite happily in semi-shade. Rhubarb needs a lot of nutrients to thrive so dig the ground to a depth of 24 inches and work in a lot of well composted manure.  Make sure the bed has been cleared of all weeds.

The rhubarb crowns should be planted so that the top is 1 inch below soil level. although, if the soil is heavy and wet, plant them slightly higher, so that the top of the crown sits at ground level. This will help prevent rotting. Rhubarb plants  get quite large so allow a spacing of 24 to 30 inches between them. Water well in dry spells.

Do not harvest during the first year after planting as this will reduce overall plant growth. Remove a few stems the next year, then up to half from then on. Always leave some stems to allow the plant to continue growing. Whilst some gardeners advise harvesting by gently removing the stem from the crown, a sharp knife is probably easier. Cut the ripe stem at the base. After you have cut the stems, remove the leaves and toss onto the compost heap. Never eat the leaves as they are poisonous.

Technically, rhubarb can be harvested right up until autumn – but it is better to stop harvesting in July or August to allow the plant to build up its energy for the winter. Allow the foliage to die back naturally in autumn then cut away the old leaves to expose the growing tips to winter cold.