Tomato Plant Vigour

In this week’s Newsletter: Tomato plant vigour, growing tomatoes outside, the limiting factor and containers for final position planting.

Tomato Plant Vigour

We all want our plants to grow as quickly as possible – that’s why it’s easy to over water and over feed them – kill them with kindness as it were!

Some plants are more vigorous and grow more quickly than others.

Generally, hybrid F1’s are more vigorous than standard open pollinated plants. If you wish to grow a large variety, it’s good to choose a hybrid. Because of its vigour, it is more likely to succeed in a poor summer.

Grafted plants are often more vigorous than hybrids because the rootstock, which is also a hybrid F1, is bred for vigour and soil borne disease resistance usually giving a higher yield.

The variety attached to the rootstock, the plant grafted onto the top, is called the scion and is our chosen variety – usually popular for its taste.

If we graft Gardener’s Delight (open pollinated), we would get a slightly more disease resistant and vigorous version of the plant we know and love. However, GD is already a fairly vigorous – easy to grow cherry –  so it probably isn’t worth the extra bother and expense and it would still be susceptible to blight if grown outside. The rootstock is disease resistant to soil borne disease but doesn’t protect the plant above (the scion) from blight.


The best combination for outside growing

The ultimate variety for growing outside, in my opinion, is a grafted, blight resistant variety such as Crimson Crush.

Tomato plant vigour
Seedlings with grafting clips.


Spending money on a grafted plant that could succumb to blight – highly likely in the UK – would be very disappointing!

For growing inside a greenhouse, the blight resistance is not as important but resistance to soil borne diseases and vigour is.

Of course, grafted plants are expensive to buy and fiddly to graft yourself – temperature and humidity need to be kept at a constant level for the graft to take.

So for growing outside, the ultimate, most likely to succeed, tomato variety is a blight resistant grafted hybrid, you get the vigour, the disease resistance, the blight resistance, the yield and the taste!


Crimson Crush – Grafted Super Plugs


By the way, don’t remove the grafting clips – they will be discarded automatically as the stems grow. The joins are very fragile!


The Limiting Factor

Whether we grow open pollinated, F1 hybrids or grafted tomato plants, we all want our plants to get the best growing conditions so that they grow quickly.

One way to get the best performance from our plants is to be able to recognise the limiting factor.

The limiting factor is whatever a plant needs most.

Here are a few of the most common deficiencies – limiting factors:

  • Not enough light (sunshine).
  • Too much or not enough water
  • Nutrient deficiency
  • Low or very high temperatures
  • A problem with the soil,
  • High humidity etc.


Being able to recognise what is holding a plant back from optimum growth, means that we can make changes and get the best results.

Of course, we can’t always make the sun shine, but we can increase reflected light.

More on “The Limiting Factor”.

Now is the time to sow!

This week I’ve been potting up some of my seedlings, from the seed tray to their first individual home.

If you haven’t sown your seeds yet, you’ll need to get cracking! By the end of the month it is best to buy plug plants or buy tomato plants at the garden centre.

Look for stocky plants that aren’t too tall. Nice medium/dark green leaves and not in flower.


What’s your final position?

Looking ahead, now is a good time to plan your final position … are you going to use grow bags and grow pots or a self watering planter such as the Quadgrow or Oasesbox?


Grow Pots In Grow Bag
Grow Pots in Grow Bag – AKA Ring Culture.


Click Photo for More About The Oasesbox


That’s it for this week… always very happy to hear from you and find out how your seedlings are getting on!





4 Responses

  1. Jess Allaway
    | Reply

    Hi Nick,
    Enjoying newsletter as usual. Many thanks. Unfortunately I was struck down by a really bad viral infection for three whole weeks just as my seedlings were reaching individual 3″ pot stage and for the first time ever they were left to get a bit stretched. Have now got them into tall narrow plastic glasses as they were all about 4″ high. In your experience, will this affect their long term performance? Weather has been pretty good here for last four weeks, very cold but dry and bright and really quite warm last few days, so the plants should catch up fast.
    Thanks too to Rhys for all his info.


    • Nick
      | Reply

      Hi Jess,
      Sorry to hear that you have been poorly – I hope you are feeling much better now!
      If seedlings get a bit too leggy, it does affect later performance but with some warm bright weather, they may thicken up their stems. You may like to sow a few extra just in case!
      Best wishes,

  2. Nick
    | Reply

    Hi Rhys,
    My seedlings have been out enjoying the sun too.
    It is a relief to see some good warm and sunny weather – let’s hope it continues!

  3. Rhys Jaggar
    | Reply

    Our first warm and sunny day of 2018 today – my Maskotka and Red Alerts are enjoying 6hrs outdoors today in 15cm pots. With temperatures in the 20s next week, plant growth should accelerate.

    The sowings around the equinox are looking really good and my last sowings come on 17th and 24th (for outdoors and competitions respectively).

    I am fairly settled on a Quadgrow for competition Sungolds and Zeniths; breathable fabric pots for bush varieties (Maskotka and Super Marmande); 15cm pots for early Red Alerts; 30 cm pots for cordon varieties; and 35 litre pots for big beefsteaks (Black Russian).

    With the lack of sun in March this year, sowing around the equinox has probably been an inspired choice…..

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