I planted seedlings from a reputable source just before May 24 in my 6 x3 foot planters on my terrace. Once in, they began grow, and then the rain came. We had loads of it, and everything seems trapped in time. The little tomatoes that had started just stopped growing . They are not rotten, or shriveled… the just seem to have paused? The beds were built last year, and good quality triple mix was used. The beds we built “self watering “ using a coil of corrugated sleeved perforated pipe in the base. The planter were great last year, bumper veggie crop.
Now, everything is in perpetual adolescence? The only thing I can think is the roots stayed too wet for too long? It’s something about these big containers, as the smaller pots are fine.
I face east, but as I’m on the roof of the house, I have full Sun all day.
I am sorry to read that your vegetable crop is struggling this year. I think that you are right about the heavy rains causing your self watering system to fail. I agree that the soil in your planter became waterlogged, which depleted the oxygen levels in the soil creating a poor growing environment.
Without adequate oxygen levels the plant roots die back and the plants are unable to take up enough soil nutrients to grow at a healthy rate. With less healthy roots the plants may be able to stay alive, but unless they can recover over the next few weeks they are unlikely to thrive.
Adequate oxygen levels in the soil help to suppress diseases in plant roots, like root rot or Pythium species. The more oxygen available to your vegetable roots, the more beneficial microbes will proliferate. Microbes such as Mycorrhiza attach to plant roots and help your plants to take up more available nutrients.
Several things you mentioned were helpful in working out what may have gone wrong. Does your sleeved corrugated perforated drain pipe have an overflow? Self watering systems in outside planters are prone to getting overwatered, so need to have an outlet to allow water to escape out of the planter when the water reaches a maximum level.
This level needs to be near the base of the planter, so that the perforated pipe can continue to take in excess water from the soil- even during heavy rainfalls.
Failure of the sleeves on drain pipes is another common problem. The sleeve fabric needs to remain permeable to function. Over time most fabrics silt up and significantly reduce the drainage rate, allowing water to accumulate in the soil. The water displaces the oxygen in your soil and your plants begin to drown.
4 oz non woven double punched geotextile would be ideal for your planter. It is designed for high water flow, which is important in an outside planter system to prevent a backup of water going into the planter drain.
You mentioned that your planters are filled with triple mix. Triple mix contains peat moss, which is added to the mix because it has excellent water retention ability. This slows down drainage to the base of the planter and can hold water around the plant roots. This is fine until the planter gets overwatered and the soil becomes saturated.
To increase drainage I recommend checking that you have an overflow and that it isn’t blocked, checking the patency of your drain pipe sleeve (and possibly upgrading it to a high flow 4 oz fabric), and adding a few inches of organic compost to your soil each fall and turning it into the soil in spring before planting the new crop.
The compost can help to aerate the soil and promote the growth of the good soil organisms that will support healthy growth in your plants. I hope next years crop is a bumper!
July 6, 2024