In this blog series, we will hear monthly top tips from expert tomato grower Terry Marshall. Terry was given his first garden for his 7th birthday and has been gardening ever since. In those days most gardeners were ‘organic’, although the phrase had yet to be coined. After a conventional horticultural college education, he eventually became a commercial glasshouse grower specialising in tomato growing. Alarmed by the ever increasing use of pesticides and herbicide's, he decided to return to his organic roots, in Bingley, where for 40 years he has been a freelance organic gardener, researcher, speaker and writer.
The photo shows Terry's great grandson and his late wife Jennifer at the show bench in 2019. All the tomatoes on the table were grown from seed in Dalefoot Compost. Terry has compiled 'Terry's Top Tips' for Dalefoot users in memory of Jennifer and her support and enthusiasm'
Terry's top tips, 5. Support
When your first tomatoes start to form and the plant is carrying four to six trusses, ask yourself ‘just how much does your tomato plant weigh?’ This may sound academic, but it is essential when it comes to support.
At this stage of growth with the weight of stem, leaves and developing fruit, a vigorous variety - and tomato plants growing in Dalefoot Compost are certainly that - can weigh in at 10lbs plus! Weight enough to snap thin twine or kink stems that slip down the canes. After all the efforts of growing them, to see maturing plants collapse is a pitiful sight.
Tomato plants can be securely supported in three ways - strings, canes and spirals. Strings need to be soft yet strong enough to carry the weight. Most spools of jute on offer these days are 3 ply. Specialist suppliers, however, still make 5 ply, this is strong enough for all but record-breaking crops. If only a few plants are being grown the simplest way is to make two suitable lengths of 3 ply, twist it together and make a soft strong cord.
With the string, make a figure of eight loop to allow for expansion and tie it round the stem below the bottom leaves. The top of the twine should be tied to a wire fastened above the plants to the greenhouse structure. The string should then be twisted round the plant as it grows. In a lightweight aluminium greenhouse, the structure may not be strong enough to take the weight and the wire may need fastening to a free standing support dug into the border at the end of the rows.
Canes are often the choice when growing in light structures. Sturdy canes are expensive but when cleaned and stored well should last for years. The plant stem is tied every 12 to 15 inches with either stem ties, soft twine or tape, as illustrated. To prevent a very heavy crop from slipping and kinking the stem, tie a length of soft twine tightly above a cane node then round the stem thus ensuring firm support.
The simplest way of supporting tomato plants by far is with spirals. These are also expensive but should last a lifetime. Some of mine are now 28 years old! The top of the spiral is best held in position with a non-load bearing wire.
Spirals are pushed into place and the plant planted close to them. Throughout the season all that is required once a week is the growing tip of the plant to be gently moved into the centre of the spiral, the plant does the rest of the work. We do not know what the season will bring each year, but a well supported plant should safely carry a very heavy crop.
Terry's top tips, 4. Planting
To produce a heavy crop of delicious fruit, a tomato needs a healthy root system with a mixture of deep plant-anchoring roots and fibrous feeding roots.
Plants growing in the greenhouse or outdoor beds have access to space to develop their root system. The roots of a vigorous variety can extend up to six feet. Roots confined to a pot, container, or growbag, mainly grow plenty of fibrous roots to take advantage of every bit of space.
A healthy greenhouse soil enriched with a large bucketful of Dalefoot Wool Compost for Tomatoes per square yard should provide sufficient nutrients for the season without the need to add fertiliser. A simple pH test showing a pH of between 6 to 6.75 is fine. When half the propagated plants are showing one open flower it is time to plant them all.
When spacing most greenhouse varieties aim for between 15 to 18 inches (38-45 cms) between plants with 15 inches (38 cms) between double rows. A week or 10 days before planting, check the temperature of the soil in the border, 6 inches down, it is easier with the soil thermometer but an ordinary air type handled carefully will do the job. Tomatoes plants will not root out into soil at a temperature of less than 14.5 degrees centigrade If the temperature is below this, ridge up the soil to expose more surface area to warmth, then when warm enough level out and plant the tomato plants.
Terry’s Top Tips, 3. Propagation
From yoghurt tubs to the latest bamboo pots, tomatoes are often propagated in whatever is to hand. This begs the question what is the optimum size of pot to propagate our tomatoes in? Ideally, we are after a plant that is wider than it is tall with well-shaped dark green hairy leaves. If the plant still has cotyledons, side leaves attached to it, it is a sign that up to this stage the plant has not suffered any form of growth check.
For gardeners in most parts of the country, it is as well to allow for a possible delay in planting out due to cold weather conditions. Tomato plants will not root out into compost or soil with a temperature of less than 14.5 degrees C. For many years I have used 5 inch 13 centimetre pots which produce lovely plants with a built in hold ability.
Tomato plants are known as ‘gross feeders’ but at this stage of their lives they need a potting compost that will feed the developing plant without being too strong that it inhibits extensive root development. Dalefoot Compost for vegetables and salads does this admirably and remains moist between watering.
When the cotyledon - seed leaves of the germinated seedling - start to touch one another it is time to transfer them to their propagating pots. A day before potting up, bring a bag of Dalefoot Vegetable and Salads Compost indoors to warm up. Half fill a 5 inch pot with Vegetable and Salad compost and carefully lift the seedling with as much root ball as possible into place in the pot adding compost to fill it, then gently firm the plant in position. Add more compost if needed and give a little water so the compost is uniformly moist.
Place the pots in the best spot to get the most available light. Ideally, if possible, keep the plants as near to a temperature of 19 to 21 degrees Centigrade by day and 13 to 15 degrees Centigrade by night to produce sturdy plants. When the leaves of the plants start to touch, space the plants out to give them more room to develop.
Terry’s Top Tips, 2. Sowing and germination.
Flavour, that's what it's all about! - The second instalment of author and expert tomato grower Terry Marshall’s top tips...
Having chosen your flavoursome varieties, it is time to get sowing. Many of those beguiling varieties that are now available, work out at 30 to 40 Pence and even up to 75 Pence per seed so 100% germination is essential. Anything less makes each plant expensive so let’s look at how to do this.
Although tomatoes will germinate over a range of temperatures, researchers tell us that 20 degrees centigrade is the optimum temperature for the maximum number of seeds to germinate.
A maximum/minimum thermometer is an invaluable aid to tomato growing. With one, local temperatures can be checked, serving to determine just where is the best place to germinate your seeds. The ideal is a thermostatically controlled propagator but for the past forty years I have used the airing cupboard for early crops with the door open 3 inches. I’ve found it maintains a constant 68 Fahrenheit or 20 degrees Centigrade. Dalefoot Seed Compost comes in a 12-litre bag so it is easy to bring a bag into the house and bring it up to temperature a day before sowing.
Fill a clean tray with moist Dalefoot Seed Compost, level and gently compress it. Sow the seed spaced 5 centimetres apart and 1 to 1.5 centimetres deep and cover the seed with fine compost. Water gently with tepid water and allow to drain. Then, place where it is possible to maintain as nearer temperature to 20 degrees centigrade.
Given good conditions, many modern hybrids may germinate in four to five days if an airing cupboard or a dark place has been used. Do make sure to check the seed tray at least twice a day after the first four days. Forget to do this and in 24 hours the seedlings could become very thin white little corkscrews which is undesirable. Once germinated, place the seed tray in as light a position as possible as near to 20 degrees by day and 13 degrees at night as can be maintained. Keep the top of the compost moist with tepid water or a water spray, taking care not to over water.
Next time; propagation, pots, light and temperature.
Terry’s Top Tips, 1. Getting started, choosing tomato seed
Warm, sweet, succulent tomatoes…sun ripened globes of delight with their blend of sugar and acid and that distinct smell. The very thought of them lifts the spirits on a cold winter's day. So, lets make this a reality…by making 2021 the year of our best tomato crop ever...
The difference between a heavy crop of delicious fruit and a mediocre one is by using our personal facilities to grow a crop within the natural laws that govern the plant. We will look at these laws and how they apply as the season progresses.
With so many varieties of tomato available which ones shall we choose? After carefully reading the details of variety, size, colour, flavour, early or main crop, disease resistance, cordon, bush, dwarf or family preferences!
Broadly speaking, cherries along with early varieties, given good growing conditions will produce ripe tomatoes 15 to 17 weeks after sowing. Some of the larger beef steaks will take a month longer and in a poor summer 22 to 24 weeks before the first fruits are ripe.
For many years, I started the season with ‘Stupice’ an old Czech variety which will produce ripe fruit 16 weeks after sowing and grow at lower temperatures than most other varieties. Another very useful variety is ‘Red Alert’. This 18 to 24 inch tall plant can easily be grown in a 10 inch pot or container and can be moved around to make take advantage of any odd spot with good light and warmth early in the year. Later it can be pruned back to produce new growth for a second crop in autumn.
Next time…Sowing and germination