You say “tomato” I say “tomato”.

There are confusions in many areas of life and tomato growing isn’t free from them. One of which is the meaning of compost for tomatoes.

Basically there are two types of compost:

  1. Multi-purpose compost – sometimes known as potting compost.
  2. Home made compost – green material etc. that’s been composted.
Compost for tomatoes - growing organic tomatoes.
Compost for growing organic seeds and cuttings

Soilless and Soil-based Compost for Tomatoes

To add the the confusion there is soilless compost that usually contains sphagnum peat moss, coir, vermiculite and sometimes perlite.

Then there is soil-based compost such as John Innes which consists of loam (clay, humus and trace elements – humus turns into organic matter over time), sphagnum peat moss and sand.

But it doesn’t stop there … we also have peat free and organic compost!

Compost tea anyone?

Peat free is self explanatory and has been made by composting green waste on an industrial scale. Then there’s organic compost that is usually peat free and contains an organic nutrient supply rather than synthetic.

Best Compost for Growing Tomatoes

The best compost for growing tomatoes is the one that hold moisture and nutrients but is also free draining. Small particles (clay) hold moisture and nutrients very well. Add sand and fine gravel to make it easy to drain and you have the best of both worlds. This compost is John Innes Number Three!

Expense of Compost for Tomatoes

The most expensive part of growing tomatoes for most gardeners is buying compost.

There was a time when grow bag soil was the cheapest way to buy large amounts. Now it’s usually a 3 for 2 deal of the largest multi-purpose bags – and a bad back to boot – if your boot is big enough!

There are some good deals around, you just need to be able to visit a few garden centres to get them.

Hydroponic Tips
My interest in taking tips from hydroponic growers and applying them to standard container growing, has enabled me to reduce the size of the containers I use, and my compost bill!

It also means I can grow more plants because my containers take up less space.

I’ve mentioned in previous newsletters that a plant that receives everything it needs, and is growing in a well aerated medium, grows a smaller root system – a root system that is better able to cope with the limited space of a container.

I’m not saying that conventional methods of using only potting compost for tomatoes in large pots for a large harvest is inferior, in fact, it’s a bit like driving in a Rolls Royce – big and luxurious.

On the other hand, using smaller containers that are highly optimised is a bit like driving in an Aston Martin – you travel more quickly and it takes up less room in the garage!

For those of us who are crazy about growing tomatoes, it’s rather nice to be able to travel both ways.

However, the Aston Martin option does give the gardener with limited space, the opportunity to grow more tomatoes and in places where it may not have been possible without this option.

The Saturday Sow-Along starts this week so if you have time, you may like to view the first video – or even join in! It’s mainly for beginners, but it can be interesting to compare the results of growing in the most simplest way, compared to using more expensive equipment. Thanks to my wife Kelly for helping with the video!

I would like to show you the results so far, of:

Two seeds sown in sponges with a fully balanced seedling feed called “First Feed”.

Compared to two seedlings sown in a mix of:

Seed compost, perlite and vermiculite (of equal thirds) which reduces the amount of nutrients available to seedlings.

They have all received the same growing conditions.

Although the larger seedlings in the sponges on the right are 5 days older, I think that the results are significant.

Heartbreaker tomato seedlings

What does this show?

This takes air availability out of the equation because both have lots of air for the roots – although it could be argued that the “third mix” is a little too course for the fine roots of the seedlings on the left.

However, the main difference is the amount of available nutrients.

The larger leaf seedlings on the right have received more food than the ones with smaller leaves on the left.

Getting the right amount of food into a well aerated root system is the best way to go. This is often difficult to judge – especially when growing in compost because it is difficult to know exactly what’s in it.

The main factor to avoid leggy seedlings is light, and any amount of restricting other elements such as nutrients, water and temperature, is really just slowing growth generally.

I’ll be adding a new article about photosynthesis and tomato plants in the drop down menu at the top of this page, in a day or two.

It’s great to see the spring sunshine and to be able to put a tray of seedlings on a bright windowsill!


Not so easy this week!

Giving less food means that plants absorb more water.
Giving more food means that plants absorb less water.
Check out the article about osmosis and tomato plants.

22 Responses

  1. Peter
    | Reply

    What can I put with my tomato compost to help my toms

    • Nick
      | Reply

      Perlite is very good.

  2. Steve Sorsby
    | Reply

    Hello Nick and fellow tomato growers,
    Nick you mention growing in rootit sponges and feeding the seedlings/young plants on rootit “First feed” , Ive used the sponges for the last few seasons with brilliant results but instead of using “First Feed” I use rootit “Formulex” I bought it in a 1 litre bottle and the dilution rate is awesome 5ml per litre of tap water so as you can see the 1 litre bottle will go further than the “First Feed” , I cannot remember how much the “Formulex” was but its well worth buying it cannot be that expensive because i wouldnt have bought it if it was expensive.
    I hope you all have a great tomato growing season.

    • Nick
      | Reply

      Hi Steve,
      Sponges are excellent as you know. I’ve had a few problems with seed compost this year and very poor germination rates. The sponges give me 100% success every time – unless I use old seeds of course.
      I use “First Feed” by Rootit and “Plant Start” by Vitalink – I think they all use about the same dosage, but as you say, a litre bottle makes it better value for money.
      You have a great tomato season too!

  3. terry
    | Reply

    Hi Nick, Thank you for the video, It keeps me on the right track and I now know I am getting my Tomatos started off ok, I had doubts as a lot of my seeds did not germinate in the last few years.
    Many Thanks,

    • Nick
      | Reply

      Hi Terry,
      It sometimes happens that seeds won’t germinate – it’s usually because of wide temperature fluctuations or old seeds.

  4. sonny
    | Reply

    hi Nick
    great letter and video. i was wondering about a hanging basket for Tumbling Tom , i seen a video where they put about 10 plants in a plastic basket, is that too mutch or is that ok for Tumbling Tom. many thanks.

    • Nick
      | Reply

      Hi Sonny,
      I’m pleased you like the video and newsletter!
      The most Tumbling Toms I’ve ever put in a hanging basket is three.
      When you first put them in, as small plants, it looks like there is plenty of room, but as plants grow it can get very crowded.
      The two issues are root room and water availability. You’ll probably get just as many tomatoes from 3 plants as you would 6 because of the available root space. Also, on a hot day, each Tumbling Tom plant can use up to around 2 litres of water and the soil area wouldn’t be able to provide/hold that quantity of water for very long.
      I would just plant three.

      • stephen clark
        | Reply

        i always grow tumblers in hanging baskets and find one plant is suffice and gives great results, i have experimented over the years and find one plant works best for great yields

  5. Rhys Jaggar
    | Reply


    Those photos with the two media – how many days had your tomato plants been growing??

    My Maskotka plant after 6 weeks has its first truss and is online to be ripening in June. That’s John Innes No. 2 + Perlite currently. Must say I’d love to find ‘balanced feeds’ which make them grow even faster!! Is it your secret recipe or something we can all buy?!

    The one thing I’d say with smaller pots is that you probably need a long wall to lean your supporting canes against, as the pots aren’t tall enough to really support a cane vertically without support. Have you experience to refute that?? I can imagine, though, that you could maximise your yields/square metre of ground using smaller pots. I do wonder whether you need to add something like Osmocote to give enough nutrients, and that stuff’s quite expensive. Only alternative I can think of is some kind of mix of leaf mould and vermicompost to give you enough in a small volume….

    • Nick
      | Reply

      Hi Rhys,
      The large leaf Heartbreakers were sown 24th Feb, and the ones with smaller leaves 1 March.

      The balanced feed I use for sponges and supplemental feeding is Rootit “first feed”. This stuff contains a full range of nutrients for seedlings and ideal when sowing in sponges, plugs, perlite and vermiculte. It also works well on larger plants as a foliar feed.

      My main methods of support these days is string inside the tunnel and canes outside for the indeterminates. – I support most of my bush varieties with canes unless they are trailing.

      For feeding, I usually feed at every watering, especially in the later stages of growth but at a reduced strength making sure that the nutrient balance is correct.

      For organic feeding, I’m using chicken manure pellets, fish emulsion and seaweed extract as foliar sprays and also Bio Bloom.

      • Rhys Jaggar
        | Reply

        That information is great Nick – really interesting stuff.

        I’ll definitely have that on my list to try out in 2015.

        Just started my foliar feeding using seaweed spray on my larger plants – they seem to like it!

        Also, got purplish colours under my younger plants’ leaves so I’m giving them a bit of foliar feeding too to try and get some nutrients to where it’s needed.

        I’m just wondering whether you’ve managed to eliminate that feature of early plant life by using the Rootit products?? Would be a good reason to buy them if so……

  6. Buster
    | Reply

    Thanks for a very interesting topic as usual Nick.

    Never driven a Rolls or Aston Martin but used to drive a Mark 1 Ford Cortina. It’s body was too big for it’s engine but it was ahead of it’s time! Bit like some of my Tomato seedlings are going!!
    Nevermind. They will be potted deep & I’ll see how they go in the ‘Wickes All Purpose’ compost before final pot on.
    Also when they are potted deeper does that help more roots break out from the stem or is there no advantage for the plant.


    • Nick
      | Reply

      Hi Buster,
      I had a mark 1,2 and 3 Cortina they were very popular in their day … I think I ended up with a Maxi because I could get a Hammond organ in it.
      Deeper potting does encourage new roots to develop from the stem – as you say.

  7. john ferrier
    | Reply

    Hi Nick,
    trust you are keeping well and as usual planting plenty of tomatoes.
    Interesting reading your latest letter on compost, I buy Grow Bags in the UK and a friend of mine ships them over to France for me. I usually buy 10 bags which I use for toms and chili’s. Bush toms I grow in the garden. For the past 4 years I have used the grow bags soil on the garden and mixing with garden compost for growing tomato plants next season, plus all sorts of other things. When ready they are planted into fresh grow bags and we start all over again at the end of the season. The old mixed compost goes on the veg/flower garden. So far I have had no problems. The poly tunnel is washed out with a bleach solution and to date we have never had any virus attacks and always get a good crop of young plants. Would appreciate your thoughts on this.

    How did the white tomatoes do, I found that they went yellow as time went on and the flavor was not as one would expect.

    All the best,

    John Ferrier

    • Nick
      | Reply

      Hi John,
      Great to hear from you!
      I’m very well thanks and growing as many plants as ever.
      I think that bleach is a very good option and a lot less smelly than fluids like Jeyes.
      I did get three or four white tomatoes but they didn’t manage to ripen fully before the end of the season, but I did sow them later than I should have done. I’ve still got a few seeds left so I’ll have another go this season.
      I hope you are well too.

    • Rhys Jaggar
      | Reply


      I”ve also found that putting spent tomato compost on the garden does no harm to the vegetable patch – I think the huge network of roots provides a really good rotting mulch for the following season. Definitely works for shallots – not tried it for anything else yet – most of last years has been dumped on a shady site where I’m planting bee attractants this spring.

      • john ferrier
        | Reply

        Hi Rhys,
        Thanks your reply, I have no problems either, in fact I use a lot on the asparagus patch and it seems to work well.
        What do you think about using it mixed with garden compost and using it for seedlings.


  8. stephen clark
    | Reply

    hey Nick, all my seedlings are up and going and today they are enjoying the sun in the greenhouse but ill be bringing them indoors at night when the cold sets in, this year is experiment year for me trying all the different growing methods out there, am looking forward to your brilliant newsletters every week. happy growing everyone

    • Nick
      | Reply

      Hi Steve,
      I find experimenting one of the most exciting aspects of tomato growing … there’s always something new to learn!

  9. Laura
    | Reply

    Very informative – following your guidelines I hope to get a decent crop for the very first time ever !

    • Nick
      | Reply

      Hi Laura,
      I’m pleased you find the newsletter helpful.

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