Harvesting of Seeds

Harvesting of Seeds

Introduction:
  • Commercial flower seed production is an international business involving highly specialized growers.
  • The production activities include harvesting and processing (drying, seed sizing, pelleting and storage) of seeds.
Harvesting of Seeds
  • Optimum stage and time of harvest are critical factors in the production of optimum quality seeds.
  • Seeds are generally harvested when they are completely ripe on the plant.
  • The basic rule of harvesting is to allow the seed to mature as long as possible on the plant without the seed or fruit becoming diseased, or overly ripe.
23.1
  • Each type of plant has an optimum time for collecting the seed, but factors such as climate, weather, disease, insects, birds, or predatory mammals may require that the seed be collected at less than the optimum time
  • When the crops are judged ready for harvesting the plants are either cut as a whole or seeds harvested with different procedures.
  • Some seeds of annuals and perennials fall from the plant at ripening either due to bursting of the fruit or due to wind. Such seed capsules should be covered with muslin cloth or butter paper bags before ripening to collect the shedding seeds in bag.
  • Adverse field conditions, especially rain during the drying period, can cause seed deterioration.
  • Covering the harvested seed materials before the rain, or moving them to dry indoor, are extra efforts required in these situations.
  • In floricultural crops, the flowers are produced in a succession of about 30-60 days or even more. They mature in different times, resulting in seed harvesting at different intervals.
  • After harvest, seeds are threshed to remove the seed from the surrounding plant material. A period of air-drying is important before seeds are threshed.
  • Plant material should be spread out in thin layers until all plant material is dry; otherwise, mold, decay, and heat from decay will cause damage to the seeds. As the plant material dries, seed pods may split open or shed seed.
  • Plant material that is ready to be threshed should be brittle. Threshing is best done outside on a dry day.
  • The threshing process involves application of mechanical force using a controlled pressure and a shearing motion., and is accomplished by hand or by machine.
  • The seeds are then sieved with different types of sieve of iron mesh/plastic mesh and finally cleaned by hand winnowing to separate out the light/unviable seeds and dust particles.
  • The seeds after proper cleaning are packed in HDPE bags and kept in shady and well ventilated rooms.
  • A crop that is harvested too early may germinate well initially but the seed does not store well.
     
Table 1: The stage of seed harvest of different annual flower crops


Plant

Stages of collection

1

Alyssum maritimum

The seeds shatter easily. Remove pods when just about to dry.

2

Antirrhinum majus

Cut when just about to dry, spikes mature from lower branches onwards.

3

Arctotis stoechadifolia

Cut the whole plant when maximum amount of seed matures and then dry on canvas

4

Calendula officinalis

Seeds shatter when too dry. Collect heads when partially dry.

5

Campanula spp.

Whole plants may be harvested

6

Celosia spp.

Collect the heads when dry on the plant. Protect drying heads from rain

7

Chrysanthemum coronarium

Cut when almost all the flower heads dry.

8

Clarkia elegans

Remove seeds as they begin drying

9

Cosmos bipinnatus

Collect the seeds as pods dry

10

Dahlia variabilis

Collect the seeds as the heads dry on the plants.

11

Delphinium sp.

Collect heads of flowers as they dry. Take out tubers when plant almost dry. Store in dry and cool place.

12

Dianthus sp.

Cut the whole plant when the lower capsules begin to dry and dry in shade.

13

Dimorphotheca sp.

Seeds may shatter if allowed to dry too much on the plant. Collect individual heads as they begin to dry.

14

Gaillardia pulchella

Cut the whole plant when the maximum amount of seed is mature.

15

Gazania splendens

Cut the entire plant when the maximum amount of seed is mature and dry on canvas.

16

Godetia grandiflora

Cut the entire plant when the maximum amount of seed is mature and dry on canvas

17

Gomphrena globosa

When lower capsules open and begin drying, cut the entire plant and dry in shade.

18

Gypsophilia elegans

When the heads dry, collect individually.

19

Helianthus annus

When the majority of the capsules have turned brown, cut whole plant and on canvas

20

Iberis amara

When the flower heads dry, collect individually

21

Helichrysum bracteatum

Cut the whole plant and dry in sun set at the first signs of seeds becoming dry

22

Impatiens balsamina

When the heads become fuzzy, collect individually.

23

Lathyrus odoratus

Cut the entire plant when the maximum amount of seed is mature and spread on canvas to dry.

24

Limonium sinuatum

When the lower pods commence drying remove the entire plant and dry in shade.

25

Linaria bipartita

Cut the whole plant when the maximum amount of seed is mature and spread on canvas to dry.

26

Linum grandiflora

When the lower pods begin drying, remove the entire plant and dry in shade

27

Lupines hartwegii

Cut the entire plant when the maximum amount of seed is mature and dry on canvas.

28

Mathiola incanna

Remove individual seed pods as they dry. If allowed to dry in excess on the plants, they would burst.

29

Mesembryanthemum crimifolium

Remove the plant when seed pods begin drying. Dry in sun or shade. Single flower seeds produce 50% or more double flowering plants.

30

Molucella laevis

Whole plant should be harvested and seed should be extracted.

31

Papaver roheas

Whole plant should be harvested and seeds should be extracted by beating the plants with stick.

32

Petunia hybrida

Remove seed pods as they begin drying

33

Phlox drumondii

Remove seeds when just about to dry to prevent shattering.

34

Pimpinella monoica

Harvest umbels when completely dry and collect seeds by threshing.

35

Portulaca grandiflora

Collect when capsules begin to dry

36

Rudbeckia bicolor

When flower heads become fuzzy collect them and dry in shade

37

Salvia splendens

When seed cap dries, remove plant and dry in shade.

38

Tagetes sp.

Collect flower-heads as they dry. Plants of dwarf species should be removed when all the flower heads are dry.

39

Tithonia speciosa

Collect the flower heads as they become fuzzy and dry in shade.

40

Tropaelum majus

Collect seeds as they dry. If allowed too long on the plant they fall off

41

Viola wittrockiana

Collect seed pods when just about to dry and shatter when over dried on the plant

42

Venidium fastuosum

When flower heads become fuzzy collect them and dry in shade.

43

Zinnia elegans

Cut flower heads as they dry. Dwarf varieties may be removed when the entire flower heads dry out.



Last modified: Monday, 18 June 2012, 8:40 AM