Two Sisters Farm in Lawrence, MI: April Apple Grafting and Air Prune Box Update

Apple Grafting Update

On 4/16/2025, it was noted that these grafted plants had had too much time inside (see Figures 1-3). Too many growing degree days accumulated too quickly in the interior basement room of my house, and they broke from dormancy earlier than desired, as it was still too cold to move them fully outside into the air prune box. Plants were moved in an unheated farmhouse garage while construction of the air prune bed was finished.

As can be seen in Figures 1-3, Hudson's, William's Pride (WP) and Pristine all took off at the top (from the scion) quickly. By April 25th, almost all of the grafts had green leaves above the graft union, as is shown in Figure 4. Figure 4 also shows that many had leaves below the graft union that needed to be removed. Whenever this happened, the buds were stripped immediately. On 4/25/25, all grafts were moved into the air prune box per Figure 5.

Figure 1. Pristine (L) and Hubbardston Nonsuch (R) on 4/16/25.

Figure 2.William's Pride (L), Freedom (R, bottom), and Gilpin (R, top) on 4/16/25.

Figure 3. Hudson's Golden Gem (L) and Pink Pearl (R) on 4/16/25.

Figure 4. Green growth took off on the apples between April 16th and 25th. Again, all shoots below the graft union were pinched off. All flower buds were pinched off when spotted.

Figure 5. Plants placed in the air prune box on 4/25/2025.

Small Nut Tree Update

Figures 6 & 7 show that several nut trees were also moved from small start containers into the air prune box. While most showed a nice taproot, there was 1 oak tree that had a "confused" tap root, as is shown in Figure 7.

Figure 6. Several swamp oaks and northern pecans were planted from seed taken from the 2024 MNFGA meetings.

Figure 7. Tap root comparisons.

Air Prune Box Construction

Two air prune beds were constructed between 4/16/2025 and 4/18/2025 using a pocket hole jig, treated 2x4 lumber, and untreated cedar for everything else (per the plans published earlier). Figures 8-13 show the air prune box assembly process.

First, all wood was cut or ripped to the appropriate dimensions. Pocket holes were drilled in the shorter pieces and would face the exterior of the box when possible (Figures 8 and 9). If the fit of the boards looked good, boards were assembled vertically so that pocket hole screws could be inserted downwards into the wood (shown in Figure 10 with the treated 2x4s). Figures 11-13 show the addition of the wire mesh on the bottom. For each box, a slightly different support method was used. In the first one, a full layer of larger gauge wire with bigger holes was added to help the 1/4" hardware cloth take the weight of the soil (Figure 12). After stapling the wire mesh in place, the 2x2s were screwed onto it to increase the holding power of the wire mesh. Figure 13 shows the second method that was used, where 2 lengths of the the larger gauge wire (cut off from the larger pore mesh used in Figure 12) were run the length of the box. The 1/4" hardware cloth was stapled on top of this and then the 2x2s were again screwed onto the 1/4" hardware cloth to further hold it in place. Figure 14 shows the fully assembled finished products. Note that the 2x2 side of the bottom treated lumber piece faces up with the 2x4s on the bottom. Cement blocks were added to decrease the likelihood of root escape into the native soil.

Figure 8. Purchased boards were cut to length and pocket holes were added as appropriate. A dedicated plug-in drill was useful for the repeated pocket hole drilling.