From our perspective as sweet pea plants (Lathyrus odoratus), the ideal time for you to harvest our stems is when the lowest blossom on the raceme is just beginning to open. At this precise moment, the bud should feel soft and pliable to the touch, and you will likely see the standard (the top petal) starting to unfurl and show its full color. The one or two buds above it should be well-developed and colored but still closed. Harvesting at this stage is crucial because our flowers are at their peak of sugar and water content, having drawn maximum resources from our vascular system. If you wait until every floret is fully open, the flowers will be more mature and respire rapidly, leading to a drastically shortened vase life. Conversely, if you cut when the buds are too tight and green, they may never open in the vase, as they have not yet accumulated sufficient carbohydrates to support the immense energy required for blooming.
The timing of your harvest during the diurnal cycle is equally important to our physiology. We strongly recommend you cut our stems in the early morning, preferably just after the dew has evaporated. At this time, our tissues are fully hydrated and turgid from the cool night and our roots' work. Our carbohydrate reserves, stored as starch in our roots and stems, are at their highest after a night of no photosynthetic activity but continued respiration. This gives the cut flower a massive energy bank to draw upon during its post-harvest life. Alternatively, late evening is also acceptable as we begin to recharge our resources after the heat of the day. You must avoid harvesting during the middle of a hot, sunny day. At that time, we are often slightly stressed and dehydrated from transpiration, which places immediate strain on our cut stems and will cause them to wilt prematurely.
The technique you use to sever our stems directly impacts our ability to take up water thereafter. You must use a sharp, clean pair of scissors or pruners. A clean cut prevents crushing our delicate vascular tissues (the xylem and phloem), which are responsible for water conduction. A crushed or ragged stem end will block these vital pathways with debris and air bubbles, drastically reducing hydration. Make the cut on the main stem, just above a set of leaves or a side shoot, and at a 45-degree angle. This angled cut increases the surface area for water uptake and prevents the stem from sitting flat on the bottom of the vase, which would create a seal. Immediately after cutting, place the stem into a bucket of clean, cool water. This quick transfer is critical to prevent air from being drawn into the stem, which creates an embolism—an airlock that blocks the flow of water.
Your job is not done once we are cut. To ensure we perform our best for you in the vase, we require immediate conditioning. Keep us in a cool, dark place for several hours or overnight in a deep bucket of water. This process, known as conditioning, allows us to fully rehydrate and acclimate before the stress of being arranged. We also recommend you strip any leaves that will fall below the waterline in the vase. Submerged foliage will decay rapidly, promoting the growth of bacteria that will clog our stems and foul the water, shortening our display. Providing a fresh, clean environment and maximizing our hydration from the moment of harvest is the final key to a long and vibrant vase life.
