Fig. 1: Experimental design of cabinets

3 MATERIALS AND METHODS

3.1 Greenhouse experiment

An experiment with ungrafted tomatoes (Lycopersicon esculentum Mill. cv. Completo) and different light treatments (see chapter “3.2 Treatments”) was conducted at the Agricultural University of Iceland at Reykir during winter 2021/2022.

Completo from De Ruiter is a compact vigourous variety suitable for truss and loose harvest with a high yielding potential and uniform fruit weight of 90-95 g (De Ruiter, without year).

On 30.09.2021 seeds of tomatoes were sown in rockwool plugs. On 09.11.2021 four plants with one top/plant were planted into rockwool slabs (50 cm x 24 cm x 10 cm). On each bed were six slabs placed in three chambers. Tomatoes were transplanted in rows in three 65 cm high beds (Fig. 1) with 2,5 plants/m2. Beds were equipped with six slabs respectively 24 tops. Three replicates, one replicate in each bed consisting of two slabs (8 plants) acted as subplots for measurements. Other slabs were not measured. Due to the weekly hanging down all plants were once at the end of the bed.

N

1 ,2 3 m 0 ,3 6 m 1 ,4 5 m 0 ,3 6 m 1 ,4 5 m 0 ,3 6 m 1 ,4 5 m 0 ,3 6 m 1 ,4 5 m 0 ,3 6 m 1 ,2 3 m

3 0 30

4, 98 m 6, 12 m

1 ,0 m 3. rep. 2. rep 1. rep.

10, 06 m

Fig. 1: Experimental design of cabinets.

Shoots were regularly taken of the plants and the plants were deleafed once a week according to 15 leaves per plant. The weekly deleafing was done in the way that most of the time two leaves were taken of the bottom and one top leaf was taken at the upper flowering cluster to create a more open and generative plant habit. That