The greenhouse is the engine of the garden in spring and early summer. Although I do use it for some plants that regard it as their permanent home, and these will increase over the years, it is also very much a plant factory to fill the garden. Lots of plants are starting to go outside and be planted but I am also sowing the last annuals. The staggered sowing is partly because some plants need sowing earlier, being slow developers, but also because of space constraints. The greenhouse is almost as full as it was a month ago but things are changing. The freesias have more or less died down so have been cut back and put under the benches to remain dry over summer till being repotted in August and the same applies to the tender nerines.

Young plants from cuttings are filling their pots and need potting on. And feeding becomes more essential as bedding plants in cells get to the stage where they are ready to plant out. As they get bigger any nutrients in the compost becomes exhausted. I use a variety of feeds but feeding is tricky because of the unknown quality of composts. This year I have bought several kinds and some are frankly shocking. One ‘seed and potting compost’ seems to be almost pure bark (that is what it smells of) and has chunks and shreds 8cm (3in) long – how this is suitable for sowing seeds is beyond me. I actually tipped it on the polytunnel beds and dug it in. So I am assuming that most of these composts have very little nutrition and am feeding at least once a week. On an aside, the reason we have to put up with these awful composts is to reduce the use of peat. And I have no argument with this. I do argue that there is a legal obligation to provide goods that are ‘fit for purpose’ and many of these composts are not. I was thus surprised to hear on the radio the other day, the garden ‘expert’ recommending the use of ‘peat moss’ as a soil conditioner. I would be pilloried if I suggested such a thing in my writing, with good reason – peat is too valuable to dig into soil as a ‘conditioner’, and there are far better things to use – and I am amazed that anyone is suggesting this use for peat – I have not done it since I was 16.

Salvias can be a particular problem from seed and need high nitrogen levels when young. They seemed to be stalling so I have been feeding with a lawn fertiliser (without weedkiller) which is high in nitrogen, for the past two weeks and they are now starting to make good growth. They could be bigger but it is all about timing – they are going into a bed that still has tulips in bloom so they have at least three weeks to grow before I can plant them out.

The sunflowers also seem a bit behind but I am not worried because, again, I don’t need to plant them out for a few weeks and I don’t want them getting stunted in the trays. At the moment they should be perfect for planting out.

The variegated, annual hops, on the other hand, need to go out soon. In fact I have put them outside to harden off. I love this plant for its splashed foliage and it is a vigorous climber. The stems are rough and grab hold of anything passing – one reason I am pleased they are no longer on the bench because it was getting annoying while watering.

One batch of marigolds (‘Red Marietta’) was sown rather early and are now ready to go out. Some have been planted but some more remain, waiting for me to get the beds ready. When I plant them out I pinch off the flowers so the plants make efforts rooting and growing rather than producing seeds. But I am too fond of a bit of colour in the greenhouse to take them all off now – though I should really.

In the mini-greenhouse within the greenhouse, I have been clearing out temporary benches because I do not need the extra shelter for seedlings. I also needed the space for the cucumbers. It is usually stated that you can’t grow tomatoes and cucumbers in the same greenhouse and there is some truth in that. Cucumbers need more shade and more humidity than tomatoes so the toms are in the polytunnel and the cucumbers are in pots in the mini-greenhouse. All five seeds germinated and I have five healthy plants. It is probably too many since cues are usually very productive. But they are also very prone to root problems and can collapse without warning so a few extra is no bad thing. Growing in separate pots should mean that if one does collapse it won’t affect the others. I will put the pots on gravel in trays that I can keep wet to increase humidity, but I have to order tons of the stuff for paths so they will have to wait.