In the arboretum nursery (Week 13, Monday)

So today was my first day in the arboretum nursery. July is the month when the Kew Diploma students in the 1st year finish their classes and go back into the gardens, so with me was also a student, new to the nursery.

We were shown around, and then assigned an area to take care of.

For the next two weeks, I will have responsibility for temperate greenhouse 30A. Inside, some rootstock plants, bedding plants (i.e. Euonymus fortunei) that will be used around the Palm House, some propagated Ilex from the holly walk that need replacing, and the collection of rhododendrons that will be used to populate the new area when it is ready (as the soil is getting impoverished in the current area and the stock needs rejuvenating).

I am also looking after the two polytunnels (one here portrayed with peacock and plane, two of Kew's most characteristic sightings!) where some plants are grown on before going off to their final destination.

The day starts with taking the min/max temperatures from all the houses and polytunnels, and checking that the mist unit and hot pipe are working. Then it's watering of those plants that need it. I find this task quite daunting, as I am very conscious that overwatering can kill more than letting plants dry out. Roots cannot get oxygen from soil that is waterlogged, so they cannot perform respiration, they die and rot.

In order to check that a plant needs watering I am looking at three things:

• the surface of the soil is dry; that is not enough however, because the surface is what dries first and underneath the soil might still be wet;
• probe to see if soil is wet underneath the surface, looking under those pots that have grids instead of bottoms or even opening those pots that can be unrolled (if in doubt);
• weigh the pots: if the soil is dry they will be rather light compared to those with wet soil in.

But it is really a skill to understand when a plant really needs watering. 

What I know very well is that little and often is not the way to go with plants, so I give a good soak to the plants that need watering, going over them twice, waiting for the water to trickle out of the bottom in between the two sessions.

I try not to wet the leaves to avoid possible diseases, but it is disputed whether that might be a problem in a well ventilated environment. Scorching on wet leaves in the sun might be more of a problem

Watering took me most of the day, today, and I had just a little time left to help clean and cut back some plants that are ready to go out. My first day in the nursery flew by...