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:
- Multi-purpose compost – sometimes known as potting compost.
- Home made compost – green material etc. that’s been composted.
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.
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.
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.