This trial is comparing my normal tomato planting/watering approach to a newfangled reservoir gizmo I cobbled together.  It’s based on something I saw for sale commercially that gets good reviews.

We’re nearly three weeks in to the trial, there has been no ripe fruit to pick or weigh, but here is the comparison between groups at this point.

Group 1 – Regular planting

Cordon varieties, Ailsa craig & Sweet Million

  • plant heights – average 90cm
  • flowers – 9 or 10 trusses of flowers across 6 plants, so not many yet.
  • fruit – no fruit set


  • flowers – lots of flowers on one plant, but no fruit yet
  • fruit – one of the two plants has set fruit, plenty of it, pea sized.

Group 2 – Reservoir system

Cordon varieties, Ailsa craig & Sweet million

  • plant heights – average height 90cm
  • flowers – 11 trusses across 6 plants
  • fruit – 1 green tomato!


  • one plant has 4 trusses of flowers but no fruit
  • the other has 12 trusses of flowers, some with fruit setting, pea size at the moment


I reckon it’s roughly even stevens at the moment, not much to separate the two groups.  I think this just means that I am doing an adequate job of watering the grow-bag plants!

The reservoir tubs are getting on towards half empty, so based on consumption rates to date, they should last well over a month before needing refilling.  They are getting pretty mucky, including quite a bit of algae. It doesn’t seem to be affecting the plants which are growing away ok.


The soil in the pots is always nicely moist.  Sometimes the surface looks dry which is worrying, but a quick investigation reveals good levels of moisture underneath.   If this method proves successful, I think next year I would cover the tubs somehow, perhaps wrap them in weed matting, to prevent the light getting to the water.  That ought to discourage the algae.  I should invest in some fresh matting too – I think re-using old matting probably was a risky and certainly dirty move.

Interestingly, the reservoir plants are all noticeably lighter in colour than their counterparts in the growbags.  To my untrained eye, the growbag plants look healthier, the reservoir plants are a little washed-out looking.

Strapping fellas

 I wonder if they need a feed.  I’ve just noticed that the growbags are enriched with tomato feed, so perhaps they are at an unfair advantage.  Since the reservoir bajajas are setting fruit, I’ve given that tub a dose of tomorite, we’ll see if that makes a difference.  I’m tempted to dose the others up too.

Looking a little malnourished

So far so good, the reservoir system is working well, at least in terms of its main role, delivering a consistent supply of water to the plants.  I will certainly have no worries about their water supply whilst on holidays later in the summer, just need to add some nutrients.

I’ll be back with an update in a couple of weeks.