The weather is slightly improving, so ventilate your poly-tunnel or greenhouse as much as possible, as in the day it will get very hot as soon as the sun comes out. In the evening, it will not be a lot warmer inside the poly-tunnel, so leave the doors slightly open, except on very cold or windy nights. The problem in the evenings is that as the temperature drops the humidity will rise, and this is not healthy for your plants and can induce some diseases like mildew.
Removing lower leaves
Another thing that I tend to do at this time of the year is to remove two or three of the lower leaves. Although the leaves are there to help produce fruit and you should only remove them below the trusses that you have started to pick from later in the the season.
The reason that I remove early ones is that some of them will touch the soil and could get disease by being damp or damaged. The other reason is that I like a good air circulation at the base of the plant, this is all basic hygiene for the longevity of your crop.
I do keep on how important it is to feed your tomato plants, especially indoor ones, this will give you more production and a longer lasting crop. The only problem that I have found here in France is getting the right tomato feed. Just because it says tomato feed on the pack or bottle, it is not necessarily the right mixture. I have found that the balance of nutrients in some tomato feed is the same for flowers, which is wrong in my eyes.
Tomato plants at this time of the year need plenty of potash for the fruit and less nitrogen for growth and leaves. Most of the feed that I have found are labelled NPK 16. 1.16. That's 16% nitrogen 1% phosphates 16% potassium, with other small amounts of trace elements added.
The NPK ratings some times have different numbers i,e 3.1. 3 but basically you are looking for the right ratios. so lets take two UK feeds and have a look.
Tomorite NPK = 24% 27% 48%
Miracle Grow = 50% 17% 33%
Miracle Grow = 50% 17% 33%
Now you can see that Tomorite has a lot more (K) potash so is perfect for tomatoes.
Miracle grow which is a good feed for flowers has more (N) nitrogen so it only needed at the early stage of growth and if you have too much crop on your plants and the heads are getting a little thin. This does happen sometimes mid season, so you need to give your plants a few doses of high nitrogen feed to help add more foliage to the plants and not to concentrate so much on fruit production.
My plants here that 'Bramble' is keeping guard over are starting to get very fat stems and the fruit is not swelling as fast as I would like. This is mainly because I didn't have any high potash feed like Tomorite, just the tomato feed that I found in my garden centre in France. Luckily I am off to the UK in the morning so I will make sure I stock up on some bottles of Tomorite.
I could make my own feed as Comfrey is very high in potash and I have an article about it HERE.
However, you can never tell the strength of home made feed without a testing kit, which I do not have, so I would rather play safe and buy some. In saying that, it is a really good feed for tomatoes and used by many people, I am just a little too lazy to make it.
If Levingtons (Scotts) who make Tomorite are watching, a case of Tomorite will suffice for the mention, if you never ask you never get! But here is a link to Amazon if you want to order it on-line. I get a few pence if you use my links.