Tomato Newsletter Week Eight

Buying tomato plug plants and potted plants from the garden centre

My first encounter with a tomato plant was during a visit to a garden centre. Rows and rows of tomato plants in individual pots, ready for taking home and potting on. I bought two Moneymakers and an Alicante.

That was about thirty years ago when the selection was mainly Moneymaker and Gardener’s Delight – you were lucky to find much else, although I did once buy a Ferrari F1 (not the racing car) but a hybrid tomato variety that had an excellent taste – it grew quite quickly too!

The popularity of growing tomatoes and the varieties now available as plug plants and potted plants, has increased massively.

Between my two local garden centres there are around twenty five varieties available  – a selection that could make any seed sower turn to potted plants considering the amount of time and effort that goes into starting from seed. Though it’s nice making your own choice of which varieties to grow each season rather than relying on the local garden centre’s choice!

Grafted Plants

There is a huge selection of tomato plants available online too, included grafted plants.

Grafted plants are more expensive and vulnerable to the graft breaking if a plant is not handled with care.

The benefits of these plants include increased vigour and disease resistance. If you grow in greenhouse soil season after season, and its become a bit dodgy and disease ridden, disease resistant rootstock can keep plants healthy and productive.

However, if you use grow bags or containers with fresh multipurpose or John Innes each season, you can achieve great results from non-grafted plants.

John Innes

This type of compost is a recipe rather than a make – and it contains clay!

We usually think of clay as being a problem because many of us experience too much of it in our gardens and allotments.

However, a small amount of clay in our soil is good because it is made of very fine particles that retain moisture and nutrients.

Combining the clay with sand and grit provides the best of both worlds … the moisture/nutrient retention and free draining soil.

Bags of compost are available with “added John Innes” because of its excellent properties but the best results are usually obtained from John Innes No. 3. It’s heavy stuff owing to the ingredients, but heavy is helpful for pot stability on a windy day!

As we all know, containers come in many shapes and sizes…

There is the large tall pot – ideal for bush varieties that trail over the sides and for keeping tomatoes off the ground.

Then by contrast, there is the grow bag – plants grow just a few inches above ground level.

At first sight, we may think that the most significant difference is the amount of compost each can hold.

This is true, but there are other factors, including surface area and capillary action, plus the type of media (soil) we use.

Surface area
A large surface area has the advantage of access to air. Roots near the soil surface are able to absorb plenty of oxygen – essential for healthy growth.

However, a large surface area has the disadvantage of moisture evaporation. This can be minimised by covering the soil between the plants, sinking pots through holes in a grow bag or using grow pots (see above). Nevertheless, grow bags dry out very quickly in warm weather, especially when plants are fruiting.

A consideration when using a tall pot is the capillary ability of the soil.

A sandy soil in a tall pot may leave roots literally – high and dry. There would be plenty of oxygen available but very little moisture in the upper layer.

Capillary action and clay (John Innes)
In taller pots, it is good practice to use a compost that includes a soil based media like John Innes which contains clay (see chart above). The other option is to add plenty of perlite to the mix.

Whichever you use, it’s important that moisture can rise to the soil surface – or very near!

Weight
An advantage that clay has, apart from water holding capacity, is its weight. It may not feel like an advantage when you have to carry it home from the garden centre, but it gives pots more stability on a windy day – especially if growing bush varieties!

Pot or Grow Bag?
Given a choice, I prefer a large pot rather than grow bag, because there are more enhancements that can be made. However, using grow pots with grow bags takes the ordinary grow bag to the next level and very good results can be achieved.

Watering
There is also an issue when watering – tall pots are better watered from above, especially if the soil capillary action is poor. Watering from below, in a wide shallow pot should be fine, because the capillary action would be enough in most soils to absorb moisture to the surface.

Media
One of the best additions we can make to any soil mix is by adding perlite. It has a very good capillary action and will enhance a sandy soil greatly.

Capillary matting can also be used to help take moisture upwards to the surface level of tall pots.

Water stress and big tomatoes!

The bigger the tomatoes you grow, the better the growing medium you need to keep your plants happy and stress-free.

If you are using a reservoire system like the Quadgrow Planter or the Autopot System, a light mix of regular compost, preferably with perlite will be fine. If you are growing in ordinary pots and containers, the best results will be achieved by using John Innes – a soil that is more forgiving owing to its moisture and nutrient retention.

That’s it for this week … if you haven’t sown yet, there is not a lot of time left. Otherwise, get down to the garden center and buy a few plug plants or potted tomato plants, avaible online too of course!

Regards,

Nick